diff --git a/addons/account/models/account_fiscal_year.py b/addons/account/models/account_fiscal_year.py
index ce031fb3f59e4..8e664c2ea7257 100644
--- a/addons/account/models/account_fiscal_year.py
+++ b/addons/account/models/account_fiscal_year.py
@@ -2,7 +2,6 @@
 
 from odoo.exceptions import ValidationError
 from odoo import api, fields, models, _
-from odoo.tools import DEFAULT_SERVER_DATE_FORMAT
 
 
 from datetime import datetime
@@ -37,8 +36,8 @@ def _check_dates(self):
         '''
         for fy in self:
             # Starting date must be prior to the ending date
-            date_from = datetime.strptime(fy.date_from, DEFAULT_SERVER_DATE_FORMAT)
-            date_to = datetime.strptime(fy.date_to, DEFAULT_SERVER_DATE_FORMAT)
+            date_from = fy.date_from
+            date_to = fy.date_to
             if date_to < date_from:
                 raise ValidationError(_('The ending date must not be prior to the starting date.'))
 
diff --git a/addons/account/models/account_invoice.py b/addons/account/models/account_invoice.py
index fa235ee9d67fb..0ba6359b6af4a 100644
--- a/addons/account/models/account_invoice.py
+++ b/addons/account/models/account_invoice.py
@@ -10,7 +10,8 @@
 from werkzeug.urls import url_encode
 
 from odoo import api, exceptions, fields, models, _
-from odoo.tools import email_re, email_split, email_escape_char, float_is_zero, float_compare, pycompat
+from odoo.tools import email_re, email_split, email_escape_char, float_is_zero, float_compare, \
+    pycompat, date_utils
 from odoo.tools.misc import formatLang
 
 from odoo.exceptions import AccessError, UserError, RedirectWarning, ValidationError, Warning
@@ -216,7 +217,7 @@ def _get_payment_info_JSON(self):
         self.payments_widget = json.dumps(False)
         if self.payment_move_line_ids:
             info = {'title': _('Less Payment'), 'outstanding': False, 'content': self._get_payments_vals()}
-            self.payments_widget = json.dumps(info)
+            self.payments_widget = json.dumps(info, default=date_utils.json_default)
 
     @api.one
     @api.depends('move_id.line_ids.amount_residual')
diff --git a/addons/account/models/account_journal_dashboard.py b/addons/account/models/account_journal_dashboard.py
index 431be1b0aa81d..a8e229883d1c9 100644
--- a/addons/account/models/account_journal_dashboard.py
+++ b/addons/account/models/account_journal_dashboard.py
@@ -76,7 +76,7 @@ def build_graph_data(date, amount):
                         """
         self.env.cr.execute(query, (self.id, last_month, today))
         for val in self.env.cr.dictfetchall():
-            date = datetime.strptime(val['date'], DF)
+            date = val['date']
             if val['date'] != today.strftime(DF):  # make sure the last point in the graph is today
                 data[:0] = [build_graph_data(date, amount)]
             amount -= val['amount']
@@ -92,7 +92,7 @@ def build_graph_data(date, amount):
     @api.multi
     def get_bar_graph_datas(self):
         data = []
-        today = datetime.strptime(fields.Date.context_today(self), DF)
+        today = fields.Date.context_today(self)
         data.append({'label': _('Past'), 'value':0.0, 'type': 'past'})
         day_of_week = int(format_datetime(today, 'e', locale=self._context.get('lang') or 'en_US'))
         first_day_of_week = today + timedelta(days=-day_of_week+1)
diff --git a/addons/account/models/account_move.py b/addons/account/models/account_move.py
index bb8a29e0fb1a5..ca4e6d9d370f2 100644
--- a/addons/account/models/account_move.py
+++ b/addons/account/models/account_move.py
@@ -1,6 +1,7 @@
 # -*- coding: utf-8 -*-
 
 import time
+from datetime import date
 from collections import OrderedDict
 from odoo import api, fields, models, _
 from odoo.osv import expression
@@ -345,10 +346,10 @@ def _post_validate(self):
     @api.multi
     def _check_lock_date(self):
         for move in self:
-            lock_date = max(move.company_id.period_lock_date or '0000-00-00', move.company_id.fiscalyear_lock_date or '0000-00-00')
+            lock_date = max(move.company_id.period_lock_date or date.min, move.company_id.fiscalyear_lock_date or date.min)
             if self.user_has_groups('account.group_account_manager'):
                 lock_date = move.company_id.fiscalyear_lock_date
-            if move.date <= (lock_date or '0000-00-00'):
+            if move.date <= (lock_date or date.min):
                 if self.user_has_groups('account.group_account_manager'):
                     message = _("You cannot add/modify entries prior to and inclusive of the lock date %s") % (lock_date)
                 else:
@@ -738,7 +739,7 @@ def check_full_reconcile(self):
         total_debit = 0
         total_credit = 0
         total_amount_currency = 0
-        maxdate = '0000-00-00'
+        maxdate = date.min
         to_balance = {}
         for aml in amls:
             total_debit += aml.debit
@@ -947,7 +948,7 @@ def compute_writeoff_counterpart_vals(values):
             total = 0
             total_currency = 0
             writeoff_lines = []
-            date = time.strftime('%Y-%m-%d')
+            date = fields.Date.today()
             for vals in lines:
                 # Check and complete vals
                 if 'account_id' not in vals or 'journal_id' not in vals:
@@ -955,7 +956,7 @@ def compute_writeoff_counterpart_vals(values):
                 if ('debit' in vals) ^ ('credit' in vals):
                     raise UserError(_("Either pass both debit and credit or none."))
                 if 'date' not in vals:
-                    vals['date'] = self._context.get('date_p') or time.strftime('%Y-%m-%d')
+                    vals['date'] = self._context.get('date_p') or fields.Date.today()
                     if vals['date'] < date:
                         date = vals['date']
                 if 'name' not in vals:
@@ -1369,8 +1370,8 @@ class AccountPartialReconcile(models.Model):
     def _compute_max_date(self):
         for rec in self:
             rec.max_date = max(
-                fields.Datetime.from_string(rec.debit_move_id.date),
-                fields.Datetime.from_string(rec.credit_move_id.date)
+                rec.debit_move_id.date,
+                rec.credit_move_id.date
             )
 
     @api.model
@@ -1608,6 +1609,6 @@ def _prepare_exchange_diff_move(self, move_date, company):
         # The move date should be the maximum date between payment and invoice
         # (in case of payment in advance). However, we should make sure the
         # move date is not recorded after the end of year closing.
-        if move_date > (company.fiscalyear_lock_date or '0000-00-00'):
+        if move_date > (company.fiscalyear_lock_date or date.min):
             res['date'] = move_date
         return res
diff --git a/addons/account/models/company.py b/addons/account/models/company.py
index 89d9d9b4646be..0b5e879ce35f2 100644
--- a/addons/account/models/company.py
+++ b/addons/account/models/company.py
@@ -9,7 +9,7 @@
 from odoo.exceptions import ValidationError, UserError, RedirectWarning
 from odoo.tools.misc import DEFAULT_SERVER_DATE_FORMAT
 from odoo.tools.float_utils import float_round, float_is_zero
-from odoo.tools import DEFAULT_SERVER_DATE_FORMAT, date_utils
+from odoo.tools import date_utils
 
 
 class ResCompany(models.Model):
@@ -110,16 +110,15 @@ def _check_lock_dates(self, vals):
         :param vals: The values passed to the write method.
         '''
         period_lock_date = vals.get('period_lock_date') and\
-            time.strptime(vals['period_lock_date'], DEFAULT_SERVER_DATE_FORMAT)
+            fields.Date.from_string(vals['period_lock_date'])
         fiscalyear_lock_date = vals.get('fiscalyear_lock_date') and\
-            time.strptime(vals['fiscalyear_lock_date'], DEFAULT_SERVER_DATE_FORMAT)
+            fields.Date.from_string(vals['fiscalyear_lock_date'])
 
-        previous_month = datetime.strptime(fields.Date.today(), DEFAULT_SERVER_DATE_FORMAT) + relativedelta(months=-1)
+        previous_month = fields.Date.today() + relativedelta(months=-1)
         days_previous_month = calendar.monthrange(previous_month.year, previous_month.month)
-        previous_month = previous_month.replace(day=days_previous_month[1]).timetuple()
+        previous_month = previous_month.replace(day=days_previous_month[1])
         for company in self:
-            old_fiscalyear_lock_date = company.fiscalyear_lock_date and\
-                time.strptime(company.fiscalyear_lock_date, DEFAULT_SERVER_DATE_FORMAT)
+            old_fiscalyear_lock_date = company.fiscalyear_lock_date
 
             # The user attempts to remove the lock date for advisors
             if old_fiscalyear_lock_date and not fiscalyear_lock_date and 'fiscalyear_lock_date' in vals:
@@ -143,7 +142,7 @@ def _check_lock_dates(self, vals):
             # In case of no new period lock date in vals, fallback to the one defined in the company
             if not period_lock_date:
                 if company.period_lock_date:
-                    period_lock_date = time.strptime(company.period_lock_date, DEFAULT_SERVER_DATE_FORMAT)
+                    period_lock_date = company.period_lock_date
                 else:
                     continue
 
@@ -182,8 +181,8 @@ def compute_fiscalyear_dates(self, current_date):
         ], limit=1)
         if fiscalyear:
             return {
-                'date_from': datetime.strptime(fiscalyear.date_from, DEFAULT_SERVER_DATE_FORMAT).date(),
-                'date_to': datetime.strptime(fiscalyear.date_to, DEFAULT_SERVER_DATE_FORMAT).date(),
+                'date_from': fiscalyear.date_from,
+                'date_to': fiscalyear.date_to,
                 'record': fiscalyear,
             }
 
@@ -204,7 +203,7 @@ def compute_fiscalyear_dates(self, current_date):
             ('date_to', '>=', date_from_str),
         ], limit=1)
         if fiscalyear_from:
-            date_from = datetime.strptime(fiscalyear_from.date_to, DEFAULT_SERVER_DATE_FORMAT).date() + timedelta(days=1)
+            date_from = fiscalyear_from.date_to + timedelta(days=1)
 
         fiscalyear_to = self.env['account.fiscal.year'].search([
             ('company_id', '=', self.id),
@@ -212,7 +211,7 @@ def compute_fiscalyear_dates(self, current_date):
             ('date_to', '>=', date_to_str),
         ], limit=1)
         if fiscalyear_to:
-            date_to = datetime.strptime(fiscalyear_to.date_from, DEFAULT_SERVER_DATE_FORMAT).date() - timedelta(days=1)
+            date_to = fiscalyear_to.date_from - timedelta(days=1)
 
         return {'date_from': date_from, 'date_to': date_to}
 
diff --git a/addons/account/report/account_aged_partner_balance.py b/addons/account/report/account_aged_partner_balance.py
index fc4a7f732ea68..88a6f4e3d88aa 100644
--- a/addons/account/report/account_aged_partner_balance.py
+++ b/addons/account/report/account_aged_partner_balance.py
@@ -1,7 +1,7 @@
 # -*- coding: utf-8 -*-
 
 import time
-from odoo import api, models, _
+from odoo import api, fields, models, _
 from odoo.exceptions import UserError
 from odoo.tools import float_is_zero
 from datetime import datetime
@@ -19,7 +19,8 @@ def _get_partner_move_lines(self, account_type, date_from, target_move, period_l
         # The context key allow it to appear
         ctx = self._context
         periods = {}
-        start = datetime.strptime(date_from, "%Y-%m-%d") - relativedelta(days=1)
+        date_from = fields.Date.from_string(date_from)
+        start = date_from - relativedelta(days=1)
         for i in range(5)[::-1]:
             stop = start - relativedelta(days=period_length)
             periods[str(i)] = {
@@ -220,7 +221,7 @@ def _get_report_values(self, docids, data=None):
         docs = self.env[model].browse(self.env.context.get('active_id'))
 
         target_move = data['form'].get('target_move', 'all')
-        date_from = data['form'].get('date_from', time.strftime('%Y-%m-%d'))
+        date_from = fields.Date.from_string(data['form'].get('date_from')) or fields.Date.today()
 
         if data['form']['result_selection'] == 'customer':
             account_type = ['receivable']
diff --git a/addons/account/report/account_partner_ledger.py b/addons/account/report/account_partner_ledger.py
index ccd2c41d64769..fa7f1206cca0e 100644
--- a/addons/account/report/account_partner_ledger.py
+++ b/addons/account/report/account_partner_ledger.py
@@ -4,7 +4,6 @@
 import time
 from odoo import api, models, _
 from odoo.exceptions import UserError
-from odoo.tools import DEFAULT_SERVER_DATE_FORMAT
 
 
 class ReportPartnerLedger(models.AbstractModel):
@@ -35,7 +34,6 @@ def _lines(self, data, partner):
         lang_id = lang._lang_get(lang_code)
         date_format = lang_id.date_format
         for r in res:
-            r['date'] = datetime.strptime(r['date'], DEFAULT_SERVER_DATE_FORMAT).strftime(date_format)
             r['displayed_name'] = '-'.join(
                 r[field_name] for field_name in ('move_name', 'ref', 'name')
                 if r[field_name] not in (None, '', '/')
diff --git a/addons/account/tests/test_account_fiscal_year.py b/addons/account/tests/test_account_fiscal_year.py
index e1ce44c38fe07..85785473ee225 100644
--- a/addons/account/tests/test_account_fiscal_year.py
+++ b/addons/account/tests/test_account_fiscal_year.py
@@ -1,8 +1,8 @@
 # -*- coding: utf-8 -*-
 from odoo.addons.account.tests.account_test_classes import AccountingTestCase
-from odoo.tools import DEFAULT_SERVER_DATE_FORMAT
 
 import odoo.tests
+from odoo import fields
 
 from datetime import datetime
 
@@ -19,10 +19,10 @@ def check_compute_fiscal_year(self, company, date, expected_date_from, expected_
         :param expected_date_from: The expected date_from after computation.
         :param expected_date_to: The expected date_to after computation.
         '''
-        current_date = datetime.strptime(date, DEFAULT_SERVER_DATE_FORMAT)
+        current_date = fields.Date.from_string(date)
         res = company.compute_fiscalyear_dates(current_date)
-        self.assertEqual(res['date_from'].strftime(DEFAULT_SERVER_DATE_FORMAT), expected_date_from)
-        self.assertEqual(res['date_to'].strftime(DEFAULT_SERVER_DATE_FORMAT), expected_date_to)
+        self.assertEqual(res['date_from'], fields.Date.from_string(expected_date_from))
+        self.assertEqual(res['date_to'], fields.Date.from_string(expected_date_to))
 
     def test_default_fiscal_year(self):
         '''Basic case with a fiscal year xxxx-01-01 - xxxx-12-31.'''
diff --git a/addons/account/tests/test_reconciliation.py b/addons/account/tests/test_reconciliation.py
index f16f08baac7d7..226108ffbba00 100644
--- a/addons/account/tests/test_reconciliation.py
+++ b/addons/account/tests/test_reconciliation.py
@@ -1,4 +1,4 @@
-from odoo import api
+from odoo import api, fields
 from odoo.addons.account.tests.account_test_classes import AccountingTestCase
 from odoo.tests import tagged
 import time
diff --git a/addons/account/wizard/account_report_aged_partner_balance.py b/addons/account/wizard/account_report_aged_partner_balance.py
index c1f186b5abbca..178f1f80c380e 100644
--- a/addons/account/wizard/account_report_aged_partner_balance.py
+++ b/addons/account/wizard/account_report_aged_partner_balance.py
@@ -27,7 +27,7 @@ def _print_report(self, data):
         if not data['form']['date_from']:
             raise UserError(_('You must set a start date.'))
 
-        start = datetime.strptime(data['form']['date_from'], "%Y-%m-%d")
+        start = fields.Date.from_string(data['form']['date_from'])
 
         for i in range(5)[::-1]:
             stop = start - relativedelta(days=period_length - 1)
diff --git a/addons/account_asset/models/account_asset.py b/addons/account_asset/models/account_asset.py
index 36a4ee9ba25f1..ae0b345750854 100644
--- a/addons/account_asset/models/account_asset.py
+++ b/addons/account_asset/models/account_asset.py
@@ -7,7 +7,6 @@
 
 from odoo import api, fields, models, _
 from odoo.exceptions import UserError, ValidationError
-from odoo.tools import DEFAULT_SERVER_DATE_FORMAT as DF
 from odoo.tools import float_compare, float_is_zero
 
 
@@ -164,7 +163,7 @@ def _compute_board_amount(self, sequence, residual_amount, amount_to_depr, undon
                 if self.prorata:
                     amount = amount_to_depr / self.method_number
                     if sequence == 1:
-                        date = datetime.strptime(self.date, DF)
+                        date = self.date
                         if self.method_period % 12 != 0:
                             month_days = calendar.monthrange(date.year, date.month)[1]
                             days = month_days - date.day + 1
@@ -176,7 +175,7 @@ def _compute_board_amount(self, sequence, residual_amount, amount_to_depr, undon
                 amount = residual_amount * self.method_progress_factor
                 if self.prorata:
                     if sequence == 1:
-                        date = datetime.strptime(self.date, DF)
+                        date = self.date
                         if self.method_period % 12 != 0:
                             month_days = calendar.monthrange(date.year, date.month)[1]
                             days = month_days - date.day + 1
@@ -189,7 +188,7 @@ def _compute_board_amount(self, sequence, residual_amount, amount_to_depr, undon
     def _compute_board_undone_dotation_nb(self, depreciation_date, total_days):
         undone_dotation_number = self.method_number
         if self.method_time == 'end':
-            end_date = datetime.strptime(self.method_end, DF).date()
+            end_date = self.method_end
             undone_dotation_number = 0
             while depreciation_date <= end_date:
                 depreciation_date = date(depreciation_date.year, depreciation_date.month, depreciation_date.day) + relativedelta(months=+self.method_period)
@@ -213,12 +212,11 @@ def compute_depreciation_board(self):
 
             # if we already have some previous validated entries, starting date is last entry + method period
             if posted_depreciation_line_ids and posted_depreciation_line_ids[-1].depreciation_date:
-                last_depreciation_date = datetime.strptime(posted_depreciation_line_ids[-1].depreciation_date, DF).date()
+                last_depreciation_date = fields.Date.from_string(posted_depreciation_line_ids[-1].depreciation_date)
                 depreciation_date = last_depreciation_date + relativedelta(months=+self.method_period)
             else:
                 # depreciation_date computed from the purchase date
                 depreciation_date = self.date
-                depreciation_date = datetime.strptime(depreciation_date, DF)
                 if self.date_first_depreciation == 'last_day_period':
                     # depreciation_date = the last day of the month
                     depreciation_date = depreciation_date + relativedelta(day=31)
@@ -226,14 +224,12 @@ def compute_depreciation_board(self):
                     if self.method_period == 12:
                         depreciation_date = depreciation_date + relativedelta(month=self.company_id.fiscalyear_last_month)
                         depreciation_date = depreciation_date + relativedelta(day=self.company_id.fiscalyear_last_day)
-                        if datetime.strftime(depreciation_date, DF) < self.date:
+                        if depreciation_date < self.date:
                             depreciation_date = depreciation_date + relativedelta(years=1)
                 elif self.first_depreciation_manual_date and self.first_depreciation_manual_date != self.date:
                     # depreciation_date set manually from the 'first_depreciation_manual_date' field
                     depreciation_date = self.first_depreciation_manual_date
-                    depreciation_date = datetime.strptime(depreciation_date, DF)
 
-            depreciation_date = depreciation_date.date()
             total_days = (depreciation_date.year % 4) and 365 or 366
             month_day = depreciation_date.day
             undone_dotation_number = self._compute_board_undone_dotation_nb(depreciation_date, total_days)
@@ -252,7 +248,7 @@ def compute_depreciation_board(self):
                     'name': (self.code or '') + '/' + str(sequence),
                     'remaining_value': residual_amount,
                     'depreciated_value': self.value - (self.salvage_value + residual_amount),
-                    'depreciation_date': depreciation_date.strftime(DF),
+                    'depreciation_date': depreciation_date,
                 }
                 commands.append((0, False, vals))
 
@@ -327,7 +323,7 @@ def _get_disposal_moves(self):
 
                 # Create a new depr. line with the residual amount and post it
                 sequence = len(asset.depreciation_line_ids) - len(unposted_depreciation_line_ids) + 1
-                today = datetime.today().strftime(DF)
+                today = fields.Datetime.today()
                 vals = {
                     'amount': asset.value_residual,
                     'asset_id': asset.id,
diff --git a/addons/account_asset/models/account_invoice.py b/addons/account_asset/models/account_invoice.py
index c4b960079ec0f..c87bccf2291f6 100644
--- a/addons/account_asset/models/account_invoice.py
+++ b/addons/account_asset/models/account_invoice.py
@@ -5,7 +5,6 @@
 from dateutil.relativedelta import relativedelta
 from odoo import api, fields, models, _
 from odoo.exceptions import UserError
-from odoo.tools import DEFAULT_SERVER_DATE_FORMAT as DF
 
 from odoo.addons import decimal_precision as dp
 
@@ -65,10 +64,10 @@ def _get_asset_date(self):
             if self.invoice_id.type in ['out_invoice', 'out_refund']:
                 self.asset_mrr = self.price_subtotal_signed / months
             if self.invoice_id.date_invoice:
-                start_date = datetime.strptime(self.invoice_id.date_invoice, DF).replace(day=1)
+                start_date = self.invoice_id.date_invoice.replace(day=1)
                 end_date = (start_date + relativedelta(months=months, days=-1))
-                self.asset_start_date = start_date.strftime(DF)
-                self.asset_end_date = end_date.strftime(DF)
+                self.asset_start_date = start_date
+                self.asset_end_date = end_date
 
     @api.one
     def asset_create(self):
diff --git a/addons/account_budget/models/account_budget.py b/addons/account_budget/models/account_budget.py
index 961c957c2d7aa..b2db529a2600f 100644
--- a/addons/account_budget/models/account_budget.py
+++ b/addons/account_budget/models/account_budget.py
@@ -205,22 +205,21 @@ def _compute_practical_amount(self):
     @api.multi
     def _compute_theoritical_amount(self):
         # beware: 'today' variable is mocked in the python tests and thus, its implementation matter
-        today = fields.Datetime.from_string(fields.Date.today())
+        today = fields.Date.today()
         for line in self:
             if line.paid_date:
-                if fields.Datetime.to_string(today) <= line.paid_date:
+                if today <= line.paid_date:
                     theo_amt = 0.00
                 else:
                     theo_amt = line.planned_amount
             else:
-                line_timedelta = fields.Datetime.from_string(line.date_to) - fields.Datetime.from_string(
-                    line.date_from)
-                elapsed_timedelta = today - fields.Datetime.from_string(line.date_from)
+                line_timedelta = line.date_to - line.date_from
+                elapsed_timedelta = today - line.date_from
 
                 if elapsed_timedelta.days < 0:
                     # If the budget line has not started yet, theoretical amount should be zero
                     theo_amt = 0.00
-                elif line_timedelta.days > 0 and today < fields.Datetime.from_string(line.date_to):
+                elif line_timedelta.days > 0 and today < line.date_to:
                     # If today is between the budget line date_from and date_to
                     theo_amt = (elapsed_timedelta.total_seconds() / line_timedelta.total_seconds()) * line.planned_amount
                 else:
@@ -265,14 +264,14 @@ def action_open_budget_entries(self):
     @api.one
     @api.constrains('date_from', 'date_to')
     def _line_dates_between_budget_dates(self):
-        budget_date_from = fields.Datetime.from_string(self.crossovered_budget_id.date_from)
-        budget_date_to = fields.Datetime.from_string(self.crossovered_budget_id.date_to)
+        budget_date_from = self.crossovered_budget_id.date_from
+        budget_date_to = self.crossovered_budget_id.date_to
         if self.date_from:
-            date_from = fields.Datetime.from_string(self.date_from)
+            date_from = self.date_from
             if date_from < budget_date_from or date_from > budget_date_to:
                 raise ValidationError(_('"Start Date" of the budget line should be included in the Period of the budget'))
 
         if self.date_to:
-            date_to = fields.Datetime.from_string(self.date_to)
+            date_to = self.date_to
             if date_to < budget_date_from or date_to > budget_date_to:
                 raise ValidationError(_('"End Date" of the budget line should be included in the Period of the budget'))
diff --git a/addons/account_budget/tests/test_theoreticalamount.py b/addons/account_budget/tests/test_theoreticalamount.py
index 082d39b9b14a0..c8341e92cf01d 100644
--- a/addons/account_budget/tests/test_theoreticalamount.py
+++ b/addons/account_budget/tests/test_theoreticalamount.py
@@ -35,29 +35,32 @@ def setUp(self):
             'account_ids': [(4, account_rev.id, 0)],
         })
         #create the budget and budget lines
-        first_january = datetime.now().replace(day=1, month=1)
+        first_january = Datetime.now().replace(day=1, month=1)
         self.last_day_of_budget = first_january + timedelta(days=364)  # will be 30th of December or 31th in case of leap year
 
+        date_from = first_january.date()
+        date_to = self.last_day_of_budget.date()
+
         crossovered_budget = self.env['crossovered.budget'].create({
             'name': 'test budget name',
-            'date_from': str(first_january.date()),
-            'date_to': str(self.last_day_of_budget.date()),
+            'date_from': date_from,
+            'date_to': date_to,
         })
         crossovered_budget_line_obj = self.env['crossovered.budget.lines']
         self.line = crossovered_budget_line_obj.create({
             'crossovered_budget_id': crossovered_budget.id,
             'general_budget_id': buget_post.id,
-            'date_from': str(first_january.date()),
-            'date_to': str(self.last_day_of_budget.date()),
+            'date_from': date_from,
+            'date_to': date_to,
             'planned_amount': -364,
         })
         self.paid_date_line = crossovered_budget_line_obj.create({
             'crossovered_budget_id': crossovered_budget.id,
             'general_budget_id': buget_post.id,
-            'date_from': str(first_january.date()),
-            'date_to': str(self.last_day_of_budget.date()),
+            'date_from': date_from,
+            'date_to': date_to,
             'planned_amount': -364,
-            'paid_date': str(datetime.now().year) + '-09-09',
+            'paid_date':  Date.today().replace(day=9, month=9),
         })
 
         self.patcher = patch('odoo.addons.account_budget.models.account_budget.fields.Date', wraps=Date)
@@ -74,7 +77,7 @@ def test_theoritical_amount_without_paid_date(self):
         ]
         for date, expected_amount in test_list:
             _logger.info("Checking theoritical amount for the date: " + date)
-            self.mock_date.today.return_value = date
+            self.mock_date.today.return_value = Date.from_string(date)
             self.assertAlmostEqual(self.line.theoritical_amount, expected_amount)
             #invalidate the cache of the budget lines to recompute the theoritical amount at next iteration
             self.line.invalidate_cache()
@@ -84,13 +87,13 @@ def test_theoritical_amount_with_paid_date(self):
             (str(datetime.now().year) + '-01-01', 0),
             (str(datetime.now().year) + '-01-02', 0),
             (str(datetime.now().year) + '-09-08', 0),
-            (str(datetime.now().year) + '-09-09', -364),
+            (str(datetime.now().year) + '-09-09', 0),
             (str(datetime.now().year) + '-09-10', -364),
             (str(self.last_day_of_budget.date()), -364),
         ]
         for date, expected_amount in test_list:
             _logger.info("Checking theoritical amount for the date: " + date)
-            self.mock_date.today.return_value = date
+            self.mock_date.today.return_value = Date.from_string(date)
             self.assertAlmostEqual(self.paid_date_line.theoritical_amount, expected_amount)
             #invalidate the cache of the budget lines to recompute the theoritical amount at next iteration
             self.paid_date_line.invalidate_cache()
diff --git a/addons/bus/models/bus.py b/addons/bus/models/bus.py
index 39de41ec0a22e..cdeee00a313a5 100644
--- a/addons/bus/models/bus.py
+++ b/addons/bus/models/bus.py
@@ -10,6 +10,7 @@
 import odoo
 from odoo import api, fields, models, SUPERUSER_ID
 from odoo.tools.misc import DEFAULT_SERVER_DATETIME_FORMAT
+from odoo.tools import date_utils
 
 _logger = logging.getLogger(__name__)
 
@@ -20,7 +21,7 @@
 # Bus
 #----------------------------------------------------------
 def json_dump(v):
-    return json.dumps(v, separators=(',', ':'))
+    return json.dumps(v, separators=(',', ':'), default=date_utils.json_default)
 
 def hashable(key):
     if isinstance(key, list):
diff --git a/addons/bus/models/bus_presence.py b/addons/bus/models/bus_presence.py
index b9f4a3ea8c67b..c1da707b21562 100644
--- a/addons/bus/models/bus_presence.py
+++ b/addons/bus/models/bus_presence.py
@@ -43,11 +43,11 @@ def update(self, inactivity_period):
         # update the presence or a create a new one
         if not presence:  # create a new presence for the user
             values['user_id'] = self._uid
-            values['last_presence'] = last_presence.strftime(DEFAULT_SERVER_DATETIME_FORMAT)
+            values['last_presence'] = last_presence
             self.create(values)
         else:  # update the last_presence if necessary, and write values
-            if datetime.datetime.strptime(presence.last_presence, DEFAULT_SERVER_DATETIME_FORMAT) < last_presence:
-                values['last_presence'] = last_presence.strftime(DEFAULT_SERVER_DATETIME_FORMAT)
+            if presence.last_presence < last_presence:
+                values['last_presence'] = last_presence
             # Hide transaction serialization errors, which can be ignored, the presence update is not essential
             with tools.mute_logger('odoo.sql_db'):
                 presence.write(values)
diff --git a/addons/calendar/models/calendar.py b/addons/calendar/models/calendar.py
index 49ab6f28fb696..556ea3578a2af 100644
--- a/addons/calendar/models/calendar.py
+++ b/addons/calendar/models/calendar.py
@@ -351,7 +351,7 @@ def do_check_alarm_for_one_date(self, one_date, event, event_maxdelta, in_the_ne
 
     @api.model
     def get_next_mail(self):
-        now = fields.Datetime.now()
+        now = fields.Datetime.to_string(fields.Datetime.now())
         last_notif_mail = self.env['ir.config_parameter'].sudo().get_param('calendar.last_notif_mail', default=now)
 
         try:
@@ -391,7 +391,7 @@ def get_next_mail(self):
                     if at_least_one and not last_found:  # if the precedent event had an alarm but not this one, we can stop the search for this event
                         break
             else:
-                in_date_format = datetime.strptime(meeting.start, DEFAULT_SERVER_DATETIME_FORMAT)
+                in_date_format = meeting.start
                 last_found = self.do_check_alarm_for_one_date(in_date_format, meeting, max_delta, 0, 'email', after=last_notif_mail, missing=True)
                 for alert in last_found:
                     self.do_mail_reminder(alert)
@@ -873,9 +873,9 @@ def _compute_dates(self):
         """
         for meeting in self:
             if meeting.allday:
-                meeting.start_date = meeting.start
+                meeting.start_date = meeting.start.date()
                 meeting.start_datetime = False
-                meeting.stop_date = meeting.stop
+                meeting.stop_date = meeting.stop.date()
                 meeting.stop_datetime = False
 
                 meeting.duration = 0.0
@@ -897,13 +897,13 @@ def _inverse_dates(self):
                 enddate = tz.localize(enddate)
                 enddate = enddate.replace(hour=18)
                 enddate = enddate.astimezone(pytz.utc)
-                meeting.stop = fields.Datetime.to_string(enddate)
+                meeting.stop = enddate
 
                 startdate = fields.Datetime.from_string(meeting.start_date)
                 startdate = tz.localize(startdate)  # Add "+hh:mm" timezone
                 startdate = startdate.replace(hour=8)  # Set 8 AM in localtime
                 startdate = startdate.astimezone(pytz.utc)  # Convert to UTC
-                meeting.start = fields.Datetime.to_string(startdate)
+                meeting.start = startdate
             else:
                 meeting.write({'start': meeting.start_datetime,
                                'stop': meeting.stop_datetime})
@@ -945,9 +945,9 @@ def _check_closing_date(self):
     @api.onchange('start_datetime', 'duration')
     def _onchange_duration(self):
         if self.start_datetime:
-            start = fields.Datetime.from_string(self.start_datetime)
+            start = self.start_datetime
             self.start = self.start_datetime
-            self.stop = fields.Datetime.to_string(start + timedelta(hours=self.duration))
+            self.stop = start + timedelta(hours=self.duration)
 
     @api.onchange('start_date')
     def _onchange_start_date(self):
@@ -971,9 +971,9 @@ def _get_ics_file(self):
         def ics_datetime(idate, allday=False):
             if idate:
                 if allday:
-                    return fields.Date.from_string(idate)
+                    return idate
                 else:
-                    return fields.Datetime.from_string(idate).replace(tzinfo=pytz.timezone('UTC'))
+                    return idate.replace(tzinfo=pytz.timezone('UTC'))
             return False
 
         try:
@@ -989,7 +989,7 @@ def ics_datetime(idate, allday=False):
 
             if not meeting.start or not meeting.stop:
                 raise UserError(_("First you have to specify the date of the invitation."))
-            event.add('created').value = ics_datetime(time.strftime(DEFAULT_SERVER_DATETIME_FORMAT))
+            event.add('created').value = ics_datetime(fields.Datetime.now())
             event.add('dtstart').value = ics_datetime(meeting.start, meeting.allday)
             event.add('dtend').value = ics_datetime(meeting.stop, meeting.allday)
             event.add('summary').value = meeting.name
@@ -1245,7 +1245,8 @@ def get_month_string(freq):
             return ''
 
         def get_end_date():
-            end_date_new = ''.join((re.compile('\d')).findall(self.final_date)) + 'T235959Z' if self.final_date else False
+            final_date = fields.Date.to_string(self.final_date)
+            end_date_new = ''.join((re.compile('\d')).findall(final_date)) + 'T235959Z' if final_date else False
             return (self.end_type == 'count' and (';COUNT=' + str(self.count)) or '') +\
                 ((end_date_new and self.end_type == 'end_date' and (';UNTIL=' + end_date_new)) or '')
 
@@ -1379,6 +1380,7 @@ def detach_recurring_event(self, values=None):
         meeting_origin = self.browse(real_id)
 
         data = self.read(['allday', 'start', 'stop', 'rrule', 'duration'])[0]
+        d_class = fields.Date if data['allday'] else fields.Datetime
         if data.get('rrule'):
             data.update(
                 values,
@@ -1387,7 +1389,8 @@ def detach_recurring_event(self, values=None):
                 rrule_type=False,
                 rrule='',
                 recurrency=False,
-                final_date=datetime.strptime(data.get('start'), DEFAULT_SERVER_DATETIME_FORMAT if data['allday'] else DEFAULT_SERVER_DATETIME_FORMAT) + timedelta(hours=values.get('duration', False) or data.get('duration'))
+                final_date=d_class.from_string(data.get('start')) \
+                    + timedelta(hours=values.get('duration', False) or data.get('duration'))
             )
 
             # do not copy the id
diff --git a/addons/calendar/tests/test_calendar.py b/addons/calendar/tests/test_calendar.py
index 12547c8f695ac..fbf86ace9e1b8 100644
--- a/addons/calendar/tests/test_calendar.py
+++ b/addons/calendar/tests/test_calendar.py
@@ -2,7 +2,7 @@
 # Part of Odoo. See LICENSE file for full copyright and licensing details.
 import datetime
 
-from datetime import datetime, timedelta
+from datetime import datetime, timedelta, time
 
 from odoo import fields
 from odoo.tests.common import TransactionCase
@@ -34,7 +34,7 @@ def test_calender_simple_event(self):
         })
 
         self.assertEqual(
-            (m.start_datetime, m.stop_datetime),
+            (str(m.start_datetime), str(m.stop_datetime)),
             (u'2017-07-12 14:30:00', u'2017-07-12 15:00:00'),
             "Sanity check"
         )
@@ -102,8 +102,8 @@ def test_calender_event(self):
         # I create a recuring rule for my event
         calendar_event_sprint_review = self.CalendarEvent.create({
             'name': 'Begin of month meeting',
-            'start': fields.Date.today() + ' 12:00:00',
-            'stop': fields.Date.today() + ' 18:00:00',
+            'start': datetime.combine(fields.Date.today(), time(12, 0)),
+            'stop': datetime.combine(fields.Date.today(), time(18, 0)),
             'recurrency': True,
             'rrule': 'FREQ=MONTHLY;INTERVAL=1;COUNT=12;BYDAY=1MO'
         })
@@ -130,7 +130,7 @@ def test_validation_error(self):
             'stop': '2017-07-12 15:00:00',
         })
         self.assertEqual(
-            (m.start_datetime, m.stop_datetime),
+            (str(m.start_datetime), str(m.stop_datetime)),
             (u'2017-07-12 14:30:00', u'2017-07-12 15:00:00'),
             "Sanity check"
         )
@@ -154,11 +154,11 @@ def test_validation_error(self):
 
         records = m.detach_recurring_event(values)
         self.assertEqual(
-            (m.start_datetime, m.stop_datetime),
-            (u'2017-07-12 14:30:00', u'2017-07-12 15:00:00'),
+            (str(m.start_datetime), str(m.stop_datetime)),
+            ('2017-07-12 14:30:00', u'2017-07-12 15:00:00'),
         )
         self.assertEquals(
-            (records.start_datetime, records.stop_datetime),
+            (str(records.start_datetime), str(records.stop_datetime)),
             (u'2017-07-10 15:30:00', u'2017-07-10 16:00:00'),
         )
 
@@ -243,7 +243,7 @@ def test_event_activity(self):
         self.assertEqual(test_record.activity_ids.summary, test_name)
         self.assertEqual(test_record.activity_ids.note, test_description)
         self.assertEqual(test_record.activity_ids.user_id, self.env.user)
-        self.assertEqual(test_record.activity_ids.date_deadline, fields.Date.to_string((now + timedelta(days=-1)).date()))
+        self.assertEqual(test_record.activity_ids.date_deadline, (now + timedelta(days=-1)).date())
 
         # updating event should update activity
         test_event.write({
@@ -255,7 +255,7 @@ def test_event_activity(self):
         self.assertEqual(test_record.activity_ids.summary, '%s2' % test_name)
         self.assertEqual(test_record.activity_ids.note, test_description2)
         self.assertEqual(test_record.activity_ids.user_id, test_user)
-        self.assertEqual(test_record.activity_ids.date_deadline, fields.Date.to_string((now + timedelta(days=-2)).date()))
+        self.assertEqual(test_record.activity_ids.date_deadline, (now + timedelta(days=-2)).date())
 
         # deleting meeting should delete its activity
         test_record.activity_ids.unlink()
@@ -268,8 +268,8 @@ def test_event_activity(self):
         ).create({
             'name': test_name,
             'description': test_description,
-            'start': fields.Datetime.to_string(now + timedelta(days=-1)),
-            'stop': fields.Datetime.to_string(now + timedelta(hours=2)),
+            'start': now + timedelta(days=-1),
+            'stop': now + timedelta(hours=2),
             'user_id': self.env.user.id,
         })
         self.assertEqual(test_event.res_model, test_record._name)
diff --git a/addons/calendar_sms/models/calendar.py b/addons/calendar_sms/models/calendar.py
index d22200b936323..986a46e521014 100644
--- a/addons/calendar_sms/models/calendar.py
+++ b/addons/calendar_sms/models/calendar.py
@@ -39,7 +39,7 @@ def get_next_mail(self):
         """ Cron method, overriden here to send SMS reminders as well
         """
         result = super(AlarmManager, self).get_next_mail()
-        now = fields.Datetime.now()
+        now = fields.Datetime.to_string(fields.Datetime.now())
         last_sms_cron = self.env['ir.config_parameter'].get_param('calendar_sms.last_sms_cron', default=now)
         cron = self.env['ir.model.data'].get_object('calendar', 'ir_cron_scheduler_alarm')
 
diff --git a/addons/crm/models/crm_lead.py b/addons/crm/models/crm_lead.py
index d1032e34b1d8f..35806bddb6fc9 100644
--- a/addons/crm/models/crm_lead.py
+++ b/addons/crm/models/crm_lead.py
@@ -1054,7 +1054,7 @@ def retrieve_sales_dashboard(self):
         meetings = self.env['calendar.event'].search(meetings_domain)
         for meeting in meetings:
             if meeting['start']:
-                start = datetime.strptime(meeting['start'], tools.DEFAULT_SERVER_DATETIME_FORMAT).date()
+                start = meeting['start']
                 if start == today:
                     result['meeting']['today'] += 1
                 if today <= start <= today + timedelta(days=7):
diff --git a/addons/event/models/event.py b/addons/event/models/event.py
index 8902bbcaa4939..0ff913fb42b9e 100644
--- a/addons/event/models/event.py
+++ b/addons/event/models/event.py
@@ -347,7 +347,7 @@ class EventRegistration(models.Model):
     partner_id = fields.Many2one(
         'res.partner', string='Contact',
         states={'done': [('readonly', True)]})
-    date_open = fields.Datetime(string='Registration Date', readonly=True, default=lambda self: fields.datetime.now())  # weird crash is directly now
+    date_open = fields.Datetime(string='Registration Date', readonly=True, default=lambda self: fields.Datetime.now())  # weird crash is directly now
     date_closed = fields.Datetime(string='Attended Date', readonly=True)
     event_begin_date = fields.Datetime(string="Event Start Date", related='event_id.date_begin', readonly=True)
     event_end_date = fields.Datetime(string="Event End Date", related='event_id.date_end', readonly=True)
@@ -515,8 +515,8 @@ def action_send_badge_email(self):
     @api.multi
     def get_date_range_str(self):
         self.ensure_one()
-        today = fields.Datetime.from_string(fields.Datetime.now())
-        event_date = fields.Datetime.from_string(self.event_begin_date)
+        today = fields.Datetime.now()
+        event_date = self.event_begin_date
         diff = (event_date.date() - today.date())
         if diff.days <= 0:
             return _('today')
diff --git a/addons/event/models/event_mail.py b/addons/event/models/event_mail.py
index 680e1d4ba8a62..3c725af4dd151 100644
--- a/addons/event/models/event_mail.py
+++ b/addons/event/models/event_mail.py
@@ -97,7 +97,7 @@ def _compute_scheduled_date(self):
             else:
                 date, sign = self.event_id.date_end, 1
 
-            self.scheduled_date = datetime.strptime(date, tools.DEFAULT_SERVER_DATETIME_FORMAT) + _INTERVALS[self.interval_unit](sign * self.interval_nbr)
+            self.scheduled_date = date + _INTERVALS[self.interval_unit](sign * self.interval_nbr)
 
     @api.one
     def execute(self):
@@ -190,7 +190,7 @@ def execute(self):
     def _compute_scheduled_date(self):
         if self.registration_id:
             date_open = self.registration_id.date_open
-            date_open_datetime = date_open and datetime.strptime(date_open, tools.DEFAULT_SERVER_DATETIME_FORMAT) or fields.datetime.now()
+            date_open_datetime = date_open or fields.Datetime.now()
             self.scheduled_date = date_open_datetime + _INTERVALS[self.scheduler_id.interval_unit](self.scheduler_id.interval_nbr)
         else:
             self.scheduled_date = False
diff --git a/addons/event/tests/test_event_flow.py b/addons/event/tests/test_event_flow.py
index 216a581538274..8d3d460462cab 100644
--- a/addons/event/tests/test_event_flow.py
+++ b/addons/event/tests/test_event_flow.py
@@ -120,7 +120,7 @@ def test_event_date_range(self):
         self.patcher = patch('odoo.addons.event.models.event.fields.Datetime', wraps=Datetime)
         self.mock_datetime = self.patcher.start()
 
-        self.mock_datetime.now.return_value = Datetime.to_string(datetime.datetime(2015, 12, 31, 12, 0))
+        self.mock_datetime.now.return_value = datetime.datetime(2015, 12, 31, 12, 0)
 
         self.event_0.registration_ids.event_begin_date = datetime.datetime(2015, 12, 31, 18, 0)
         self.assertEqual(self.event_0.registration_ids.get_date_range_str(), u'today')
@@ -131,7 +131,7 @@ def test_event_date_range(self):
         self.event_0.registration_ids.event_begin_date = datetime.datetime(2016, 1, 2, 6, 0)
         self.assertEqual(self.event_0.registration_ids.get_date_range_str(), u'in 2 days')
 
-        self.mock_datetime.now.return_value = Datetime.to_string(datetime.datetime(2015, 12, 10, 12, 0))
+        self.mock_datetime.now.return_value = datetime.datetime(2015, 12, 10, 12, 0)
         self.event_0.registration_ids.event_begin_date = datetime.datetime(2016, 1, 25, 6, 0)
         self.assertEqual(self.event_0.registration_ids.get_date_range_str(), u'next month')
 
diff --git a/addons/event/tests/test_mail_schedule.py b/addons/event/tests/test_mail_schedule.py
index 010e5aa87a5d0..0e8f665f1d81a 100644
--- a/addons/event/tests/test_mail_schedule.py
+++ b/addons/event/tests/test_mail_schedule.py
@@ -13,7 +13,7 @@ class TestMailSchedule(TestEventCommon):
     @mute_logger('odoo.addons.base.models.ir_model', 'odoo.models')
     def test_00_event_mail_schedule(self):
         """ Test mail scheduling for events """
-        now = fields.datetime.now()
+        now = fields.Datetime.now()
         event_date_begin = now + relativedelta(days=1)
         event_date_end = now + relativedelta(days=3)
 
@@ -56,7 +56,7 @@ def test_00_event_mail_schedule(self):
         # verify that subscription scheduler was auto-executed after each registration
         self.assertEqual(len(schedulers[0].mail_registration_ids), 2, 'event: incorrect number of mail scheduled date')
 
-        mails = self.env['mail.mail'].search([('subject', 'ilike', 'registration'), ('date', '>=', datetime.datetime.strftime(now, tools.DEFAULT_SERVER_DATETIME_FORMAT))], order='date DESC', limit=3)
+        mails = self.env['mail.mail'].search([('subject', 'ilike', 'registration'), ('date', '>=', now)], order='date DESC', limit=3)
         self.assertEqual(len(mails), 2, 'event: wrong number of registration mail sent')
 
         for registration in schedulers[0].mail_registration_ids:
@@ -65,7 +65,7 @@ def test_00_event_mail_schedule(self):
         # check before event scheduler
         schedulers = self.EventMail.search([('event_id', '=', test_event.id), ('interval_type', '=', 'before_event')])
         self.assertEqual(len(schedulers), 1, 'event: wrong scheduler creation')
-        self.assertEqual(schedulers[0].scheduled_date, datetime.datetime.strftime(event_date_begin + relativedelta(days=-1), tools.DEFAULT_SERVER_DATETIME_FORMAT), 'event: incorrect scheduled date')
+        self.assertEqual(schedulers[0].scheduled_date, event_date_begin + relativedelta(days=-1), 'event: incorrect scheduled date')
 
         # execute event reminder scheduler explicitly
         schedulers[0].execute()
@@ -73,7 +73,7 @@ def test_00_event_mail_schedule(self):
         self.assertTrue(schedulers[0].mail_sent, 'event: reminder scheduler should have sent an email')
         self.assertTrue(schedulers[0].done, 'event: reminder scheduler should be done')
 
-        mails = self.env['mail.mail'].search([('subject', 'ilike', 'TestEventMail'), ('date', '>=', datetime.datetime.strftime(now, tools.DEFAULT_SERVER_DATETIME_FORMAT))], order='date DESC', limit=3)
+        mails = self.env['mail.mail'].search([('subject', 'ilike', 'TestEventMail'), ('date', '>=', now)], order='date DESC', limit=3)
         self.assertEqual(len(mails), 3, 'event: wrong number of reminders in outgoing mail queue')
 
 
diff --git a/addons/fleet/models/fleet_vehicle.py b/addons/fleet/models/fleet_vehicle.py
index 6f19be439fc6d..609ecbe6e4f43 100644
--- a/addons/fleet/models/fleet_vehicle.py
+++ b/addons/fleet/models/fleet_vehicle.py
@@ -299,9 +299,9 @@ def _compute_vehicle_log_name(self):
         for record in self:
             name = record.vehicle_id.name
             if not name:
-                name = record.date
+                name = str(record.date)
             elif record.date:
-                name += ' / ' + record.date
+                name += ' / ' + str(record.date)
             record.name = name
 
     @api.onchange('vehicle_id')
diff --git a/addons/fleet/models/fleet_vehicle_cost.py b/addons/fleet/models/fleet_vehicle_cost.py
index 95d7b5fc9cadd..f066286c38840 100644
--- a/addons/fleet/models/fleet_vehicle_cost.py
+++ b/addons/fleet/models/fleet_vehicle_cost.py
@@ -145,7 +145,7 @@ def _compute_contract_name(self):
             if record.cost_subtype_id.name:
                 name += ' / ' + record.cost_subtype_id.name
             if record.date:
-                name += ' / ' + record.date
+                name += ' / ' + str(record.date)
             record.name = name
 
     @api.depends('expiration_date', 'state')
@@ -231,7 +231,7 @@ def scheduler_manage_auto_costs(self):
             if not contract.start_date or contract.cost_frequency == 'no':
                 continue
             found = False
-            last_cost_date = contract.start_date
+            startdate = contract.start_date
             if contract.generated_cost_ids:
                 last_autogenerated_cost = VehicleCost.search([
                     ('contract_id', '=', contract.id),
@@ -239,12 +239,11 @@ def scheduler_manage_auto_costs(self):
                 ], offset=0, limit=1, order='date desc')
                 if last_autogenerated_cost:
                     found = True
-                    last_cost_date = last_autogenerated_cost.date
-            startdate = fields.Date.from_string(last_cost_date)
+                    startdate = last_autogenerated_cost.date.date()
             if found:
                 startdate += deltas.get(contract.cost_frequency)
-            today = fields.Date.from_string(fields.Date.context_today(self))
-            while (startdate <= today) & (startdate <= fields.Date.from_string(contract.expiration_date)):
+            today = fields.Date.context_today(self)
+            while (startdate <= today) & (startdate <= contract.expiration_date):
                 data = {
                     'amount': contract.cost_generated,
                     'date': fields.Date.context_today(self),
diff --git a/addons/gamification/models/challenge.py b/addons/gamification/models/challenge.py
index 93cd77a22cddc..48868407f249c 100644
--- a/addons/gamification/models/challenge.py
+++ b/addons/gamification/models/challenge.py
@@ -141,11 +141,11 @@ def _get_next_report_date(self):
         report period.
         """
         for challenge in self:
-            last = fields.Datetime.from_string(challenge.last_report_date).date()
+            last = challenge.last_report_date
             offset = self.REPORT_OFFSETS.get(challenge.report_message_frequency)
 
             if offset:
-                challenge.next_report_date = fields.Date.to_string(last + offset)
+                challenge.next_report_date = last + offset
             else:
                 challenge.next_report_date = False
 
diff --git a/addons/google_calendar/models/google_calendar.py b/addons/google_calendar/models/google_calendar.py
index a422438778ce5..b02f7586e75c2 100644
--- a/addons/google_calendar/models/google_calendar.py
+++ b/addons/google_calendar/models/google_calendar.py
@@ -193,12 +193,12 @@ class GoogleCalendar(models.AbstractModel):
     def generate_data(self, event, isCreating=False):
         if event.allday:
             start_date = event.start_date
-            final_date = (datetime.strptime(event.stop_date, tools.DEFAULT_SERVER_DATE_FORMAT) + timedelta(days=1)).strftime(tools.DEFAULT_SERVER_DATE_FORMAT)
+            final_date = event.stop_date + timedelta(days=1)
             type = 'date'
             vstype = 'dateTime'
         else:
-            start_date = fields.Datetime.context_timestamp(self, fields.Datetime.from_string(event.start)).isoformat('T')
-            final_date = fields.Datetime.context_timestamp(self, fields.Datetime.from_string(event.stop)).isoformat('T')
+            start_date = fields.Datetime.context_timestamp(self, event.start).isoformat('T')
+            final_date = fields.Datetime.context_timestamp(self, event.stop).isoformat('T')
             type = 'dateTime'
             vstype = 'date'
         attendee_list = []
@@ -852,9 +852,9 @@ def update_events(self, lastSync=False):
         return True
 
     def check_and_sync(self, oe_event, google_event):
-        if datetime.strptime(oe_event.oe_update_date, "%Y-%m-%d %H:%M:%S.%f") > datetime.strptime(google_event['updated'], "%Y-%m-%dT%H:%M:%S.%fz"):
+        if oe_event.oe_update_date > datetime.strptime(google_event['updated'], "%Y-%m-%dT%H:%M:%S.%fz"):
             self.update_to_google(oe_event, google_event)
-        elif datetime.strptime(oe_event.oe_update_date, "%Y-%m-%d %H:%M:%S.%f") < datetime.strptime(google_event['updated'], "%Y-%m-%dT%H:%M:%S.%fz"):
+        elif oe_event.oe_update_date < datetime.strptime(google_event['updated'], "%Y-%m-%dT%H:%M:%S.%fz"):
             self.update_from_google(oe_event, google_event, 'write')
 
     def get_sequence(self, instance_id):
diff --git a/addons/hr_attendance/models/hr_attendance.py b/addons/hr_attendance/models/hr_attendance.py
index 7a88460c20a60..cadccfcf6d0e0 100644
--- a/addons/hr_attendance/models/hr_attendance.py
+++ b/addons/hr_attendance/models/hr_attendance.py
@@ -1,10 +1,7 @@
 # -*- coding: utf-8 -*-
 # Part of Odoo. See LICENSE file for full copyright and licensing details.
 
-from datetime import datetime
-
 from odoo import models, fields, api, exceptions, _
-from odoo.tools import DEFAULT_SERVER_DATETIME_FORMAT
 
 
 class HrAttendance(models.Model):
@@ -43,8 +40,7 @@ def name_get(self):
     def _compute_worked_hours(self):
         for attendance in self:
             if attendance.check_out:
-                delta = datetime.strptime(attendance.check_out, DEFAULT_SERVER_DATETIME_FORMAT) - datetime.strptime(
-                    attendance.check_in, DEFAULT_SERVER_DATETIME_FORMAT)
+                delta = attendance.check_out - attendance.check_in
                 attendance.worked_hours = delta.total_seconds() / 3600.0
 
     @api.constrains('check_in', 'check_out')
diff --git a/addons/hr_contract/tests/test_auto_status.py b/addons/hr_contract/tests/test_auto_status.py
index fb755bdb82f63..efb7de51f9ae0 100644
--- a/addons/hr_contract/tests/test_auto_status.py
+++ b/addons/hr_contract/tests/test_auto_status.py
@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 # Part of Odoo. See LICENSE file for full copyright and licensing details.
-from datetime import datetime
+from datetime import date, datetime
 from odoo.tests.common import TransactionCase
 from dateutil.relativedelta import relativedelta
 
@@ -37,13 +37,13 @@ def test_contract_enddate(self):
         self.assertEquals(self.contract.state, 'close')
 
     def test_contract_pending_visa_expire(self):
-        self.employee.visa_expire = datetime.now() + relativedelta(days=30)
+        self.employee.visa_expire = date.today() + relativedelta(days=30)
         self.test_contract.update(dict(date_end=False))
         self.contract = self.contracts.create(self.test_contract)
         self.apply_cron()
         self.assertEquals(self.contract.state, 'pending')
 
-        self.employee.visa_expire = datetime.now() + relativedelta(days=-5)
+        self.employee.visa_expire = date.today() + relativedelta(days=-5)
         self.test_contract.update({
             'date_start': datetime.now() + relativedelta(days=-50),
             'state': 'pending',
diff --git a/addons/hr_holidays/models/hr_leave.py b/addons/hr_holidays/models/hr_leave.py
index 523f2b5a6952b..c2e2e2df44f07 100644
--- a/addons/hr_holidays/models/hr_leave.py
+++ b/addons/hr_holidays/models/hr_leave.py
@@ -376,12 +376,12 @@ def add_follower(self, employee_id):
     def _check_leave_type_validity(self):
         for leave in self:
             if leave.holiday_status_id.validity_start and leave.holiday_status_id.validity_stop:
-                vstart = fields.Datetime.from_string(leave.holiday_status_id.validity_start)
-                vstop  = fields.Datetime.from_string(leave.holiday_status_id.validity_stop)
-                dfrom  = fields.Datetime.from_string(leave.date_from)
-                dto    = fields.Datetime.from_string(leave.date_to)
+                vstart = leave.holiday_status_id.validity_start
+                vstop  = leave.holiday_status_id.validity_stop
+                dfrom  = leave.date_from
+                dto    = leave.date_to
 
-                if dfrom and dto and (dfrom < vstart or dto > vstop):
+                if dfrom and dto and (dfrom.date() < vstart or dto.date() > vstop):
                     raise UserError(_('You can take %s only between %s and %s') % (leave.holiday_status_id.display_name, \
                                                                                   leave.holiday_status_id.validity_start, leave.holiday_status_id.validity_stop))
 
diff --git a/addons/hr_holidays/models/hr_leave_allocation.py b/addons/hr_holidays/models/hr_leave_allocation.py
index 1f5274dda95bc..297a510030a50 100644
--- a/addons/hr_holidays/models/hr_leave_allocation.py
+++ b/addons/hr_holidays/models/hr_leave_allocation.py
@@ -288,9 +288,9 @@ def add_follower(self, employee_id):
     def _check_leave_type_validity(self):
         for allocation in self:
             if allocation.holiday_status_id.validity_start and allocation.holiday_status_id.validity_stop:
-                vstart = fields.Datetime.from_string(allocation.holiday_status_id.validity_start)
-                vstop = fields.Datetime.from_string(allocation.holiday_status_id.validity_stop)
-                today = fields.Datetime.from_string(fields.Datetime.now())
+                vstart = allocation.holiday_status_id.validity_start
+                vstop = allocation.holiday_status_id.validity_stop
+                today = fields.Date.today()
 
                 if vstart > today or vstop < today:
                     raise UserError(_('You can allocate %s only between %s and %s') % (allocation.holiday_status_id.display_name,
diff --git a/addons/hr_holidays/tests/test_accrual_allocations.py b/addons/hr_holidays/tests/test_accrual_allocations.py
index 3a3d1150f3adc..8250f88f0a75b 100644
--- a/addons/hr_holidays/tests/test_accrual_allocations.py
+++ b/addons/hr_holidays/tests/test_accrual_allocations.py
@@ -90,7 +90,7 @@ def test_accrual_base_leaves(self):
 
         employee = self.env['hr.employee'].browse(self.employee_hruser_id)
         # Getting the previous work date
-        df = employee.resource_calendar_id.plan_days(-2, fields.Datetime.from_string(fields.Datetime.now())).date()
+        df = employee.resource_calendar_id.plan_days(-2, fields.Datetime.now()).date()
 
         leave_0 = Leave.create({
             'name': 'Leave for hruser',
@@ -173,7 +173,7 @@ def test_accrual_new_employee(self):
         """
         Allocation = self.env['hr.leave.allocation'].sudo(self.user_hrmanager_id).with_context(tracking_disable=True)
 
-        self.set_employee_create_date(self.employee_emp_id, fields.Datetime.now())
+        self.set_employee_create_date(self.employee_emp_id, fields.Datetime.to_string(fields.Datetime.now()))
 
         alloc_0 = Allocation.create({
             'name': 'one shot one kill',
diff --git a/addons/hr_recruitment/models/hr_recruitment.py b/addons/hr_recruitment/models/hr_recruitment.py
index 67ca1548bfd04..6149bc159f704 100644
--- a/addons/hr_recruitment/models/hr_recruitment.py
+++ b/addons/hr_recruitment/models/hr_recruitment.py
@@ -1,9 +1,7 @@
 # -*- coding: utf-8 -*-
 # Part of Odoo. See LICENSE file for full copyright and licensing details.
 
-from datetime import datetime
-
-from odoo import api, fields, models, tools, SUPERUSER_ID
+from odoo import api, fields, models, SUPERUSER_ID
 from odoo.tools.translate import _
 from odoo.exceptions import UserError
 
@@ -176,13 +174,13 @@ def _default_company_id(self):
     @api.one
     def _compute_day(self):
         if self.date_open:
-            date_create = datetime.strptime(self.create_date, tools.DEFAULT_SERVER_DATETIME_FORMAT)
-            date_open = datetime.strptime(self.date_open, tools.DEFAULT_SERVER_DATETIME_FORMAT)
+            date_create = self.create_date
+            date_open = self.date_open
             self.day_open = (date_open - date_create).total_seconds() / (24.0 * 3600)
 
         if self.date_closed:
-            date_create = datetime.strptime(self.create_date, tools.DEFAULT_SERVER_DATETIME_FORMAT)
-            date_closed = datetime.strptime(self.date_closed, tools.DEFAULT_SERVER_DATETIME_FORMAT)
+            date_create = self.create_date
+            date_closed = self.date_closed
             self.day_close = (date_closed - date_create).total_seconds() / (24.0 * 3600)
             self.delay_close = self.day_close - self.day_open
 
diff --git a/addons/l10n_be_hr_payroll_fleet/models/fleet.py b/addons/l10n_be_hr_payroll_fleet/models/fleet.py
index 4605584cb0dc3..c72f10117baf8 100644
--- a/addons/l10n_be_hr_payroll_fleet/models/fleet.py
+++ b/addons/l10n_be_hr_payroll_fleet/models/fleet.py
@@ -5,7 +5,7 @@
 
 from odoo import api, fields, models
 
-from odoo.fields import Datetime
+from odoo.fields import Datetime, Date
 
 
 class FleetVehicle(models.Model):
@@ -80,17 +80,18 @@ def create(self, vals):
     def _get_acquisition_date(self):
         self.ensure_one()
         return babel.dates.format_date(
-            date=Datetime.from_string(self.acquisition_date),
+            date=self.acquisition_date,
             format='MMMM y',
             locale=self._context.get('lang') or 'en_US'
         )
 
     def _get_car_atn(self, acquisition_date, car_value, fuel_type, co2):
         # Compute the correction coefficient from the age of the car
-        now = Datetime.from_string(Datetime.now())
-        start = Datetime.from_string(acquisition_date)
-        if start:
-            number_of_month = (now.year - start.year) * 12.0 + now.month - start.month + int(bool(now.day - start.day + 1))
+        now = Date.today()
+        if acquisition_date:
+            number_of_month = ((now.year - acquisition_date.year) * 12.0 + now.month -
+                               acquisition_date.month +
+                               int(bool(now.day - acquisition_date.day + 1)))
             if number_of_month <= 12:
                 age_coefficient = 1.00
             elif number_of_month <= 24:
diff --git a/addons/l10n_fr_fec/wizard/account_fr_fec.py b/addons/l10n_fr_fec/wizard/account_fr_fec.py
index bd8e4cc44c0e6..b18518cffe0cb 100644
--- a/addons/l10n_fr_fec/wizard/account_fr_fec.py
+++ b/addons/l10n_fr_fec/wizard/account_fr_fec.py
@@ -5,11 +5,10 @@
 
 import base64
 import io
-from datetime import datetime
 
 from odoo import api, fields, models, _
 from odoo.exceptions import Warning
-from odoo.tools import pycompat, DEFAULT_SERVER_DATE_FORMAT
+from odoo.tools import pycompat
 
 
 class AccountFrFec(models.TransientModel):
@@ -68,7 +67,7 @@ def do_query_unaffected_earnings(self):
             '''
         company = self.env.user.company_id
         formatted_date_from = self.date_from.replace('-', '')
-        date_from = datetime.strptime(self.date_from, DEFAULT_SERVER_DATE_FORMAT)
+        date_from = self.date_from
         formatted_date_year = date_from.year
         self._cr.execute(
             sql_query, (formatted_date_year, formatted_date_from, formatted_date_from, formatted_date_from, self.date_from, company.id))
@@ -174,7 +173,7 @@ def generate_fec(self):
         AND aat.type not in ('receivable', 'payable')
         '''
         formatted_date_from = self.date_from.replace('-', '')
-        date_from = datetime.strptime(self.date_from, DEFAULT_SERVER_DATE_FORMAT)
+        date_from = self.date_from
         formatted_date_year = date_from.year
         self._cr.execute(
             sql_query, (formatted_date_year, formatted_date_from, formatted_date_from, formatted_date_from, self.date_from, company.id))
diff --git a/addons/l10n_in_hr_payroll/report/report_payroll_advice.py b/addons/l10n_in_hr_payroll/report/report_payroll_advice.py
index 0a29469440448..51bc88994ede0 100644
--- a/addons/l10n_in_hr_payroll/report/report_payroll_advice.py
+++ b/addons/l10n_in_hr_payroll/report/report_payroll_advice.py
@@ -2,7 +2,6 @@
 # Part of Odoo. See LICENSE file for full copyright and licensing details.
 
 import time
-from datetime import datetime
 
 from odoo import api, models
 
@@ -16,8 +15,8 @@ def get_month(self, input_date):
                }
         slip = self.env['hr.payslip'].search([('date_from', '<=', input_date), ('date_to', '>=', input_date)], limit=1)
         if slip:
-            from_date = datetime.strptime(slip.date_from, '%Y-%m-%d')
-            to_date = datetime.strptime(slip.date_to, '%Y-%m-%d')
+            from_date = slip.date_from
+            to_date = slip.date_to
             res['from_name'] = from_date.strftime('%d') + '-' + from_date.strftime('%B') + '-' + from_date.strftime('%Y')
             res['to_name'] = to_date.strftime('%d') + '-' + to_date.strftime('%B') + '-' + to_date.strftime('%Y')
         return res
diff --git a/addons/lunch/models/lunch.py b/addons/lunch/models/lunch.py
index 0108165c2b040..4decde206fda6 100644
--- a/addons/lunch/models/lunch.py
+++ b/addons/lunch/models/lunch.py
@@ -123,9 +123,9 @@ def _check_date(self):
         """
         Prevents the user to create an order in the past
         """
-        date_order = datetime.datetime.strptime(self.date, '%Y-%m-%d')
-        date_today = datetime.datetime.strptime(fields.Date.context_today(self), '%Y-%m-%d')
-        if (date_order < date_today):
+        date_order = self.date
+        date_today = fields.Date.context_today(self)
+        if date_order < date_today:
             raise ValidationError(_('The date of your order is in the past.'))
 
     @api.one
diff --git a/addons/mail/models/mail_activity.py b/addons/mail/models/mail_activity.py
index dbb56e2d132e5..72263a134c0d5 100644
--- a/addons/mail/models/mail_activity.py
+++ b/addons/mail/models/mail_activity.py
@@ -172,7 +172,9 @@ def _compute_state(self):
     def _onchange_activity_type_id(self):
         if self.activity_type_id:
             self.summary = self.activity_type_id.summary
-            self.date_deadline = (datetime.now() + timedelta(days=self.activity_type_id.days))
+            # Date.context_today is correct because date_deadline is a Date and is meant to be
+            # expressed in user TZ
+            self.date_deadline = fields.Date.context_today(self) + timedelta(days=self.activity_type_id.days)
 
     @api.onchange('recommended_activity_type_id')
     def _onchange_recommended_activity_type_id(self):
diff --git a/addons/mail/models/mail_template.py b/addons/mail/models/mail_template.py
index 97d141af0c76c..2aa38083d25b7 100644
--- a/addons/mail/models/mail_template.py
+++ b/addons/mail/models/mail_template.py
@@ -30,7 +30,7 @@ def format_date(env, date, pattern=False):
 
 def format_tz(env, dt, tz=False, format=False):
     record_user_timestamp = env.user.sudo().with_context(tz=tz or env.user.sudo().tz or 'UTC')
-    timestamp = datetime.datetime.strptime(dt, tools.DEFAULT_SERVER_DATETIME_FORMAT)
+    timestamp = fields.Datetime.from_string(dt)
 
     ts = fields.Datetime.context_timestamp(record_user_timestamp, timestamp)
 
diff --git a/addons/mail/models/mail_tracking_value.py b/addons/mail/models/mail_tracking_value.py
index 5e758c45482e4..874ce4fde9a35 100644
--- a/addons/mail/models/mail_tracking_value.py
+++ b/addons/mail/models/mail_tracking_value.py
@@ -46,8 +46,8 @@ def create_tracking_values(self, initial_value, new_value, col_name, col_info, t
             })
         elif col_info['type'] == 'date':
             values.update({
-                'old_value_datetime': initial_value and datetime.strftime(datetime.combine(datetime.strptime(initial_value, tools.DEFAULT_SERVER_DATE_FORMAT), datetime.min.time()), tools.DEFAULT_SERVER_DATETIME_FORMAT) or False,
-                'new_value_datetime': new_value and datetime.strftime(datetime.combine(datetime.strptime(new_value, tools.DEFAULT_SERVER_DATE_FORMAT), datetime.min.time()), tools.DEFAULT_SERVER_DATETIME_FORMAT) or False,
+                'old_value_datetime': initial_value and fields.Datetime.to_string(datetime.combine(fields.Date.from_string(initial_value), datetime.min.time())) or False,
+                'new_value_datetime': new_value and fields.Datetime.to_string(datetime.combine(fields.Date.from_string(new_value), datetime.min.time())) or False,
             })
         elif col_info['type'] == 'boolean':
             values.update({
@@ -88,8 +88,8 @@ def get_display_value(self, type):
                     result.append(record['%s_value_datetime' % type])
             elif record.field_type == 'date':
                 if record['%s_value_datetime' % type]:
-                    new_date = datetime.strptime(record['%s_value_datetime' % type], tools.DEFAULT_SERVER_DATETIME_FORMAT).date()
-                    result.append(new_date.strftime(tools.DEFAULT_SERVER_DATE_FORMAT))
+                    new_date = record['%s_value_datetime' % type]
+                    result.append(fields.Date.to_string(new_date))
                 else:
                     result.append(record['%s_value_datetime' % type])
             elif record.field_type == 'boolean':
diff --git a/addons/membership/models/account_invoice.py b/addons/membership/models/account_invoice.py
index 85b158e495944..66e4942649f90 100644
--- a/addons/membership/models/account_invoice.py
+++ b/addons/membership/models/account_invoice.py
@@ -3,6 +3,8 @@
 
 from odoo import api, fields, models
 
+from datetime import date
+
 
 class Invoice(models.Model):
     _inherit = 'account.invoice'
@@ -36,7 +38,8 @@ def write(self, vals):
                 # Product line has changed to a membership product
                 date_from = line.product_id.membership_date_from
                 date_to = line.product_id.membership_date_to
-                if line.invoice_id.date_invoice > (date_from or '0000-00-00') and line.invoice_id.date_invoice < (date_to or '0000-00-00'):
+                if (line.invoice_id.date_invoice > (date_from or date.min) and
+                        line.invoice_id.date_invoice < (date_to or date.min)):
                     date_from = line.invoice_id.date_invoice
                 MemberLine.create({
                     'partner': line.invoice_id.partner_id.id,
@@ -62,7 +65,10 @@ def create(self, vals):
             # Product line is a membership product
             date_from = invoice_line.product_id.membership_date_from
             date_to = invoice_line.product_id.membership_date_to
-            if date_from and date_from < (invoice_line.invoice_id.date_invoice or '0000-00-00') < (date_to or '0000-00-00'):
+            if (date_from and
+                    date_from <
+                    (invoice_line.invoice_id.date_invoice or date.min) <
+                    (date_to or date.min)):
                 date_from = invoice_line.invoice_id.date_invoice
             MemberLine.create({
                 'partner': invoice_line.invoice_id.partner_id.id,
diff --git a/addons/mrp/tests/test_order.py b/addons/mrp/tests/test_order.py
index 415014b6ba0fb..c3fc2a45ce3ca 100644
--- a/addons/mrp/tests/test_order.py
+++ b/addons/mrp/tests/test_order.py
@@ -59,7 +59,7 @@ def test_basic(self):
         })
         inventory.action_validate()
 
-        test_date_planned = datetime.now() - timedelta(days=1)
+        test_date_planned = Dt.now() - timedelta(days=1)
         test_quantity = 2.0
         self.bom_1.routing_id = False
         man_order = self.env['mrp.production'].sudo(self.user_mrp_user).create({
@@ -76,7 +76,7 @@ def test_basic(self):
 
         # check production move
         production_move = man_order.move_finished_ids
-        self.assertEqual(production_move.date, Dt.to_string(test_date_planned))
+        self.assertEqual(production_move.date, test_date_planned)
         self.assertEqual(production_move.product_id, self.product_4)
         self.assertEqual(production_move.product_uom, man_order.product_uom_id)
         self.assertEqual(production_move.product_qty, man_order.product_qty)
@@ -85,7 +85,7 @@ def test_basic(self):
 
         # check consumption moves
         for move in man_order.move_raw_ids:
-            self.assertEqual(move.date, Dt.to_string(test_date_planned))
+            self.assertEqual(move.date, test_date_planned)
         first_move = man_order.move_raw_ids.filtered(lambda move: move.product_id == self.product_2)
         self.assertEqual(first_move.product_qty, test_quantity / self.bom_1.product_qty * self.product_4.uom_id.factor_inv * 2)
         first_move = man_order.move_raw_ids.filtered(lambda move: move.product_id == self.product_1)
diff --git a/addons/point_of_sale/models/pos_config.py b/addons/point_of_sale/models/pos_config.py
index 7d65a44b4026e..21f70997ea947 100644
--- a/addons/point_of_sale/models/pos_config.py
+++ b/addons/point_of_sale/models/pos_config.py
@@ -6,7 +6,6 @@
 
 from odoo import api, fields, models, _
 from odoo.exceptions import ValidationError
-from odoo.tools import DEFAULT_SERVER_DATETIME_FORMAT as DATETIME_FORMAT
 
 
 class AccountCashboxLine(models.Model):
@@ -209,7 +208,7 @@ def _compute_current_session_user(self):
                 pos_config.pos_session_username = session[0].user_id.name
                 pos_config.pos_session_state = session[0].state
                 pos_config.pos_session_duration = (
-                    datetime.now() - datetime.strptime(session[0].start_at, DATETIME_FORMAT)
+                    datetime.now() - session[0].start_at
                 ).days if session[0].start_at else 0
             else:
                 pos_config.pos_session_username = False
diff --git a/addons/point_of_sale/wizard/pos_payment.py b/addons/point_of_sale/wizard/pos_payment.py
index e4b494baddea6..2b8a7eeb9a869 100644
--- a/addons/point_of_sale/wizard/pos_payment.py
+++ b/addons/point_of_sale/wizard/pos_payment.py
@@ -32,7 +32,7 @@ def _default_amount(self):
     journal_id = fields.Many2one('account.journal', string='Payment Mode', required=True, default=_default_journal)
     amount = fields.Float(digits=(16, 2), required=True, default=_default_amount)
     payment_name = fields.Char(string='Payment Reference')
-    payment_date = fields.Date(string='Payment Date', required=True, default=lambda *a: fields.Datetime.now())
+    payment_date = fields.Date(string='Payment Date', required=True, default=lambda *a: fields.Date.today())
 
     @api.onchange('session_id')
     def _on_change_session(self):
diff --git a/addons/purchase/models/purchase.py b/addons/purchase/models/purchase.py
index 36b8aa3aa8ec1..30969fa29cdb7 100644
--- a/addons/purchase/models/purchase.py
+++ b/addons/purchase/models/purchase.py
@@ -171,7 +171,7 @@ def copy(self, default=None):
         for line in new_po.order_line:
             seller = line.product_id._select_seller(
                 partner_id=line.partner_id, quantity=line.product_qty,
-                date=line.order_id.date_order and line.order_id.date_order[:10], uom_id=line.product_uom)
+                date=line.order_id.date_order and line.order_id.date_order.date(), uom_id=line.product_uom)
             line.date_planned = line._get_date_planned(seller)
         return new_po
 
@@ -526,7 +526,7 @@ def _get_date_planned(self, seller, po=False):
         """
         date_order = po.date_order if po else self.order_id.date_order
         if date_order:
-            return datetime.strptime(date_order, DEFAULT_SERVER_DATETIME_FORMAT) + relativedelta(days=seller.delay if seller else 0)
+            return date_order + relativedelta(days=seller.delay if seller else 0)
         else:
             return datetime.today() + relativedelta(days=seller.delay if seller else 0)
 
@@ -590,7 +590,7 @@ def _onchange_quantity(self):
         seller = self.product_id._select_seller(
             partner_id=self.partner_id,
             quantity=self.product_qty,
-            date=self.order_id.date_order and self.order_id.date_order[:10],
+            date=self.order_id.date_order and self.order_id.date_order.date(),
             uom_id=self.product_uom,
             params=params)
 
diff --git a/addons/purchase_requisition/models/purchase_requisition.py b/addons/purchase_requisition/models/purchase_requisition.py
index 0e96a3de9f707..d9b969ec5b91f 100644
--- a/addons/purchase_requisition/models/purchase_requisition.py
+++ b/addons/purchase_requisition/models/purchase_requisition.py
@@ -280,7 +280,7 @@ def _prepare_purchase_order_line(self, name, product_qty=0.0, price_unit=0.0, ta
             'product_qty': product_qty,
             'price_unit': price_unit,
             'taxes_id': [(6, 0, taxes_ids)],
-            'date_planned': requisition.schedule_date or fields.Date.today(),
+            'date_planned': requisition.schedule_date or fields.Datetime.now(),
             'account_analytic_id': self.account_analytic_id.id,
             'analytic_tag_ids': self.analytic_tag_ids.ids,
             'move_dest_ids': self.move_dest_id and [(4, self.move_dest_id.id)] or []
diff --git a/addons/purchase_stock/models/stock_rule.py b/addons/purchase_stock/models/stock_rule.py
index b89361f7b5d68..1419f5566f883 100644
--- a/addons/purchase_stock/models/stock_rule.py
+++ b/addons/purchase_stock/models/stock_rule.py
@@ -98,7 +98,7 @@ def _update_purchase_order_line(self, product_id, product_qty, product_uom, valu
         seller = product_id._select_seller(
             partner_id=partner,
             quantity=line.product_qty + procurement_uom_po_qty,
-            date=line.order_id.date_order and line.order_id.date_order[:10],
+            date=line.order_id.date_order and line.order_id.date_order.date(),
             uom_id=product_id.uom_po_id)
 
         price_unit = self.env['account.tax']._fix_tax_included_price_company(seller.price, line.product_id.supplier_taxes_id, line.taxes_id, values['company_id']) if seller else 0.0
@@ -118,7 +118,7 @@ def _prepare_purchase_order_line(self, product_id, product_qty, product_uom, val
         seller = product_id._select_seller(
             partner_id=partner,
             quantity=procurement_uom_po_qty,
-            date=po.date_order and po.date_order[:10],
+            date=po.date_order and po.date_order.date(),
             uom_id=product_id.uom_po_id)
 
         taxes = product_id.supplier_taxes_id
diff --git a/addons/purchase_stock/tests/test_purchase_lead_time.py b/addons/purchase_stock/tests/test_purchase_lead_time.py
index f251cf4984d20..c7bad00f5abc6 100644
--- a/addons/purchase_stock/tests/test_purchase_lead_time.py
+++ b/addons/purchase_stock/tests/test_purchase_lead_time.py
@@ -29,19 +29,17 @@ def test_00_product_company_level_delays(self):
 
         # Check order date of purchase order
         order_date = fields.Datetime.from_string(date_planned) - timedelta(days=company.po_lead) - timedelta(days=self.product_1.seller_ids.delay)
-        po_order_date = fields.Datetime.to_string(order_date)
-        self.assertEqual(purchase.date_order, po_order_date, 'Order date should be equal to: Date of the procurement order - Purchase Lead Time - Delivery Lead Time.')
+        self.assertEqual(purchase.date_order, order_date, 'Order date should be equal to: Date of the procurement order - Purchase Lead Time - Delivery Lead Time.')
 
         # Check scheduled date of purchase order
         schedule_date = order_date + timedelta(days=self.product_1.seller_ids.delay)
-        po_schedule_date = fields.Datetime.to_string(schedule_date)
-        self.assertEqual(purchase.date_planned, po_schedule_date, 'Schedule date should be equal to: Order date of Purchase order + Delivery Lead Time.')
+        self.assertEqual(purchase.date_planned, schedule_date, 'Schedule date should be equal to: Order date of Purchase order + Delivery Lead Time.')
 
         # check the picking created or not
         self.assertTrue(purchase.picking_ids, "Picking should be created.")
 
         # Check scheduled date of In Type shipment
-        self.assertEqual(purchase.picking_ids.scheduled_date, po_schedule_date, 'Schedule date of In type shipment should be equal to: schedule date of purchase order.')
+        self.assertEqual(purchase.picking_ids.scheduled_date, schedule_date, 'Schedule date of In type shipment should be equal to: schedule date of purchase order.')
 
     def test_01_product_level_delay(self):
         """ To check schedule dates of multiple purchase order line of the same purchase order,
@@ -68,21 +66,18 @@ def test_01_product_level_delay(self):
         order_line_pro_1 = purchase2.order_line.filtered(lambda r: r.product_id == self.product_1)
         order_line_pro_2 = purchase2.order_line.filtered(lambda r: r.product_id == self.product_2)
         order_date = fields.Datetime.from_string(date_planned1) - timedelta(days=self.product_1.seller_ids.delay)
-        po_order_date = fields.Datetime.to_string(order_date)
-        self.assertEqual(purchase2.date_order, po_order_date, 'Order date should be equal to: Date of the procurement order - Delivery Lead Time.')
+        self.assertEqual(purchase2.date_order, order_date, 'Order date should be equal to: Date of the procurement order - Delivery Lead Time.')
 
         # Check scheduled date of purchase order line for product_1
         schedule_date_1 = order_date + timedelta(days=self.product_1.seller_ids.delay)
-        schedule_date_line_1 = fields.Datetime.to_string(schedule_date_1)
-        self.assertEqual(order_line_pro_1.date_planned, schedule_date_line_1, 'Schedule date of purchase order line for product_1 should be equal to: Order date of purchase order + Delivery Lead Time of product_1.')
+        self.assertEqual(order_line_pro_1.date_planned, schedule_date_1, 'Schedule date of purchase order line for product_1 should be equal to: Order date of purchase order + Delivery Lead Time of product_1.')
 
         # Check scheduled date of purchase order line for product_2
         schedule_date_2 = order_date + timedelta(days=self.product_2.seller_ids.delay)
-        schedule_date_line_2 = fields.Datetime.to_string(schedule_date_2)
-        self.assertEqual(order_line_pro_2.date_planned, schedule_date_line_2, 'Schedule date of purchase order line for product_2 should be equal to: Order date of purchase order + Delivery Lead Time of product_2.')
+        self.assertEqual(order_line_pro_2.date_planned, schedule_date_2, 'Schedule date of purchase order line for product_2 should be equal to: Order date of purchase order + Delivery Lead Time of product_2.')
 
         # Check scheduled date of purchase order
-        po_schedule_date = min(schedule_date_line_1, schedule_date_line_2)
+        po_schedule_date = min(schedule_date_1, schedule_date_2)
         self.assertEqual(purchase2.date_planned, po_schedule_date, 'Schedule date of purchase order should be minimum of schedule dates of purchase order lines.')
 
         # Check the picking created or not
@@ -121,13 +116,11 @@ def test_02_product_route_level_delays(self):
 
         # Check order date of purchase order
         order_date = fields.Datetime.from_string(date_planned) - timedelta(days=self.product_1.seller_ids.delay + rule_delay)
-        po_order_date = fields.Datetime.to_string(order_date)
-        self.assertEqual(purchase.date_order, po_order_date, 'Order date should be equal to: Date of the procurement order - Delivery Lead Time(supplier and pull rules).')
+        self.assertEqual(purchase.date_order, order_date, 'Order date should be equal to: Date of the procurement order - Delivery Lead Time(supplier and pull rules).')
 
         # Check scheduled date of purchase order
         schedule_date = order_date + timedelta(days=self.product_1.seller_ids.delay + rule_delay)
-        po_schedule_date = fields.Datetime.to_string(schedule_date)
-        self.assertEqual(date_planned, po_schedule_date, 'Schedule date should be equal to: Order date of Purchase order + Delivery Lead Time(supplier and pull rules).')
+        self.assertEqual(date_planned, str(schedule_date), 'Schedule date should be equal to: Order date of Purchase order + Delivery Lead Time(supplier and pull rules).')
 
         # Check the picking crated or not
         self.assertTrue(purchase.picking_ids, "Picking should be created.")
@@ -135,10 +128,8 @@ def test_02_product_route_level_delays(self):
         # Check scheduled date of Internal Type shipment
         incoming_shipment1 = self.env['stock.picking'].search([('move_lines.product_id', 'in', (self.product_1.id, self.product_2.id)), ('picking_type_id', '=', self.warehouse_1.int_type_id.id), ('location_id', '=', self.warehouse_1.wh_input_stock_loc_id.id), ('location_dest_id', '=', self.warehouse_1.wh_qc_stock_loc_id.id)])
         incoming_shipment1_date = order_date + timedelta(days=self.product_1.seller_ids.delay)
-        incoming_shipment1_schedule_date = fields.Datetime.to_string(incoming_shipment1_date)
-        self.assertEqual(incoming_shipment1.scheduled_date, incoming_shipment1_schedule_date, 'Schedule date of Internal Type shipment for input stock location should be equal to: schedule date of purchase order + push rule delay.')
+        self.assertEqual(incoming_shipment1.scheduled_date, incoming_shipment1_date, 'Schedule date of Internal Type shipment for input stock location should be equal to: schedule date of purchase order + push rule delay.')
 
         incoming_shipment2 = self.env['stock.picking'].search([('picking_type_id', '=', self.warehouse_1.int_type_id.id), ('location_id', '=', self.warehouse_1.wh_qc_stock_loc_id.id), ('location_dest_id', '=', self.warehouse_1.lot_stock_id.id)])
         incoming_shipment2_date = schedule_date - timedelta(days=incoming_shipment2.move_lines[0].rule_id.delay)
-        incoming_shipment2_schedule_date = fields.Datetime.to_string(incoming_shipment2_date)
-        self.assertEqual(incoming_shipment2.scheduled_date, incoming_shipment2_schedule_date, 'Schedule date of Internal Type shipment for quality control stock location should be equal to: schedule date of Internal type shipment for input stock location + push rule delay..')
+        self.assertEqual(incoming_shipment2.scheduled_date, incoming_shipment2_date, 'Schedule date of Internal Type shipment for quality control stock location should be equal to: schedule date of Internal type shipment for input stock location + push rule delay..')
diff --git a/addons/sale/models/sale.py b/addons/sale/models/sale.py
index 6ae3a5ab513f7..e1d0f7319f65e 100644
--- a/addons/sale/models/sale.py
+++ b/addons/sale/models/sale.py
@@ -163,9 +163,9 @@ def _compute_access_url(self):
             order.access_url = '/my/orders/%s' % (order.id)
 
     def _compute_is_expired(self):
-        now = datetime.now()
+        today = fields.Date.today()
         for order in self:
-            if order.validity_date and fields.Datetime.from_string(order.validity_date) < now:
+            if order.validity_date and order.validity_date < today:
                 order.is_expired = True
             else:
                 order.is_expired = False
diff --git a/addons/sale_order_dates/models/sale_order.py b/addons/sale_order_dates/models/sale_order.py
index f02552adfdf78..aeb9982e03946 100644
--- a/addons/sale_order_dates/models/sale_order.py
+++ b/addons/sale_order_dates/models/sale_order.py
@@ -39,8 +39,8 @@ def _compute_expected_date(self):
     def _compute_effective_date(self):
         for order in self:
             pickings = order.picking_ids.filtered(lambda x: x.state == 'done' and x.location_dest_id.usage == 'customer')
-            dates_list = pickings.mapped('date_done')
-            order.effective_date = dates_list and min(dates_list)
+            dates_list = [date for date in pickings.mapped('date_done') if date]
+            order.effective_date = dates_list and min(dates_list).date()
 
     @api.onchange('commitment_date')
     def onchange_commitment_date(self):
diff --git a/addons/sale_order_dates/tests/test_commitment_date.py b/addons/sale_order_dates/tests/test_commitment_date.py
index 3b9494702ed53..d55b1d35134fc 100644
--- a/addons/sale_order_dates/tests/test_commitment_date.py
+++ b/addons/sale_order_dates/tests/test_commitment_date.py
@@ -17,6 +17,6 @@ def test_sale_order_commitment_date(self):
         # I verify that the Procurements and Stock Moves have been generated with the correct date
         security_delay = timedelta(days=new_order.company_id.security_lead)
         commitment_date = fields.Datetime.from_string(new_order.commitment_date)
-        right_date = fields.Datetime.to_string(commitment_date - security_delay)
+        right_date = commitment_date - security_delay
         for line in new_order.order_line:
             self.assertEqual(line.move_ids[0].date_expected, right_date, "The expected date for the Stock Move is wrong")
diff --git a/addons/sale_order_dates/tests/test_expected_date.py b/addons/sale_order_dates/tests/test_expected_date.py
index a565621cb4c7d..5286ee72dc25b 100644
--- a/addons/sale_order_dates/tests/test_expected_date.py
+++ b/addons/sale_order_dates/tests/test_expected_date.py
@@ -46,32 +46,36 @@ def test_sale_order_expected_date(self):
 
         # if Shipping Policy is set to `direct`(when SO is in draft state) then expected date should be
         # current date + shortest lead time from all of it's order lines
-        expected_date = fields.Datetime.to_string(fields.Datetime.from_string(fields.Datetime.now()) + timedelta(days=5))
-        self.assertEquals(expected_date, sale_order.expected_date, "Wrong expected date on sale order!")
+        expected_date = fields.Datetime.now() + timedelta(days=5)
+        self.assertAlmostEqual(expected_date, sale_order.expected_date,
+            msg="Wrong expected date on sale order!", delta=timedelta(seconds=1))
 
         # if Shipping Policy is set to `one`(when SO is in draft state) then expected date should be
         # current date + longest lead time from all of it's order lines
         sale_order.write({'picking_policy': 'one'})
-        expected_date = fields.Datetime.to_string(fields.Datetime.from_string(fields.Datetime.now()) + timedelta(days=15))
-        self.assertEquals(expected_date, sale_order.expected_date, "Wrong expected date on sale order!")
+        expected_date = fields.Datetime.now() + timedelta(days=15)
+        self.assertAlmostEquals(expected_date, sale_order.expected_date,
+            msg="Wrong expected date on sale order!", delta=timedelta(seconds=1))
 
         sale_order.action_confirm()
 
         # Setting confirmation date of SO to 5 days from today so that the expected/effective date could be checked
         # against real confirmation date
-        confirm_date = fields.Datetime.from_string(fields.Datetime.now()) + timedelta(days=5)
+        confirm_date = fields.Datetime.now() + timedelta(days=5)
         sale_order.write({'confirmation_date': confirm_date})
 
         # if Shipping Policy is set to `one`(when SO is confirmed) then expected date should be
         # SO confirmation date + longest lead time from all of it's order lines
-        expected_date = fields.Datetime.to_string(confirm_date + timedelta(days=15))
-        self.assertEquals(expected_date, sale_order.expected_date, "Wrong expected date on sale order!")
+        expected_date = confirm_date + timedelta(days=15)
+        self.assertAlmostEqual(expected_date, sale_order.expected_date,
+            msg="Wrong expected date on sale order!", delta=timedelta(seconds=1))
 
         # if Shipping Policy is set to `direct`(when SO is confirmed) then expected date should be
         # SO confirmation date + shortest lead time from all of it's order lines
         sale_order.write({'picking_policy': 'direct'})
-        expected_date = fields.Datetime.to_string(confirm_date + timedelta(days=5))
-        self.assertEquals(expected_date, sale_order.expected_date, "Wrong expected date on sale order!")
+        expected_date = confirm_date + timedelta(days=5)
+        self.assertAlmostEqual(expected_date, sale_order.expected_date,
+            msg="Wrong expected date on sale order!", delta=timedelta(seconds=1))
 
         # Check effective date, it should be date on which the first shipment successfully delivered to customer
         picking = sale_order.picking_ids[0]
diff --git a/addons/sale_stock/models/sale_order.py b/addons/sale_stock/models/sale_order.py
index bb469c21b866b..43ce0fbbe1732 100644
--- a/addons/sale_stock/models/sale_order.py
+++ b/addons/sale_stock/models/sale_order.py
@@ -280,13 +280,13 @@ def _prepare_procurement_values(self, group_id=False):
         """
         values = super(SaleOrderLine, self)._prepare_procurement_values(group_id)
         self.ensure_one()
-        date_planned = datetime.strptime(self.order_id.confirmation_date, DEFAULT_SERVER_DATETIME_FORMAT)\
+        date_planned = self.order_id.confirmation_date\
             + timedelta(days=self.customer_lead or 0.0) - timedelta(days=self.order_id.company_id.security_lead)
         values.update({
             'company_id': self.order_id.company_id,
             'group_id': group_id,
             'sale_line_id': self.id,
-            'date_planned': date_planned.strftime(DEFAULT_SERVER_DATETIME_FORMAT),
+            'date_planned': date_planned,
             'route_ids': self.route_id,
             'warehouse_id': self.order_id.warehouse_id or False,
             'partner_dest_id': self.order_id.partner_shipping_id
diff --git a/addons/stock/models/product.py b/addons/stock/models/product.py
index 3a9b6f0fb0cf6..5c91fff6af294 100644
--- a/addons/stock/models/product.py
+++ b/addons/stock/models/product.py
@@ -93,7 +93,9 @@ def _compute_quantities_dict(self, lot_id, owner_id, package_id, from_date=False
         domain_quant_loc, domain_move_in_loc, domain_move_out_loc = self._get_domain_locations()
         domain_quant = [('product_id', 'in', self.ids)] + domain_quant_loc
         dates_in_the_past = False
-        if to_date and to_date < fields.Datetime.now(): #Only to_date as to_date will correspond to qty_available
+        # only to_date as to_date will correspond to qty_available
+        to_date = fields.Datetime.to_datetime(to_date)
+        if to_date and to_date < fields.Datetime.now():
             dates_in_the_past = True
 
         domain_move_in = [('product_id', 'in', self.ids)] + domain_move_in_loc
diff --git a/addons/stock/models/stock_move.py b/addons/stock/models/stock_move.py
index 35b18f0f0af8a..827f9c5a6ee01 100644
--- a/addons/stock/models/stock_move.py
+++ b/addons/stock/models/stock_move.py
@@ -426,11 +426,11 @@ def write(self, vals):
                     if 'date_expected' in propagated_changes_dict:
                         propagated_changes_dict.pop('date_expected')
                     if propagated_date_field:
-                        current_date = datetime.strptime(move.date_expected, DEFAULT_SERVER_DATETIME_FORMAT)
-                        new_date = datetime.strptime(vals.get(propagated_date_field), DEFAULT_SERVER_DATETIME_FORMAT)
+                        current_date = move.date_expected
+                        new_date = fields.Datetime.from_string(vals.get(propagated_date_field))
                         delta_days = (new_date - current_date).total_seconds() / 86400
                         if abs(delta_days) >= move.company_id.propagation_minimum_delta:
-                            old_move_date = datetime.strptime(move.move_dest_ids[0].date_expected, DEFAULT_SERVER_DATETIME_FORMAT)
+                            old_move_date = move.move_dest_ids[0].date_expected
                             new_move_date = (old_move_date + relativedelta.relativedelta(days=delta_days or 0)).strftime(DEFAULT_SERVER_DATETIME_FORMAT)
                             propagated_changes_dict['date_expected'] = new_move_date
                     #For pushed moves as well as for pulled moves, propagate by recursive call of write().
diff --git a/addons/stock/models/stock_rule.py b/addons/stock/models/stock_rule.py
index c2ea9f222931a..11beb7338a25d 100644
--- a/addons/stock/models/stock_rule.py
+++ b/addons/stock/models/stock_rule.py
@@ -136,7 +136,7 @@ def _run_push(self, move):
         Care this function is not call by method run. It is called explicitely
         in stock_move.py inside the method _push_apply
         """
-        new_date = (datetime.strptime(move.date_expected, DEFAULT_SERVER_DATETIME_FORMAT) + relativedelta(days=self.delay)).strftime(DEFAULT_SERVER_DATETIME_FORMAT)
+        new_date = fields.Datetime.to_string(move.date_expected + relativedelta(days=self.delay))
         if self.auto == 'transparent':
             move.write({
                 'date': new_date,
@@ -193,7 +193,9 @@ def _get_stock_move_values(self, product_id, product_qty, product_uom, location_
         :param procurement: browse record
         :rtype: dictionary
         '''
-        date_expected = (datetime.strptime(values['date_planned'], DEFAULT_SERVER_DATETIME_FORMAT) - relativedelta(days=self.delay or 0)).strftime(DEFAULT_SERVER_DATETIME_FORMAT)
+        date_expected = fields.Datetime.to_string(
+            fields.Datetime.from_string(values['date_planned']) - relativedelta(days=self.delay or 0)
+        )
         # it is possible that we've already got some move done, so check for the done qty and create
         # a new move with the correct qty
         qty_left = product_qty
diff --git a/addons/stock/tests/test_move.py b/addons/stock/tests/test_move.py
index a65365cc801ef..f3fee888e0de5 100644
--- a/addons/stock/tests/test_move.py
+++ b/addons/stock/tests/test_move.py
@@ -3602,8 +3602,9 @@ def test_in_date_2(self):
             ('product_id', '=', self.product3.id),
             ('lot_id', '=', lot1.id),
         ])
-        from datetime import datetime, timedelta
-        initial_in_date_lot1 = datetime.now() - timedelta(days=5)
+        from odoo.fields import Datetime
+        from datetime import timedelta
+        initial_in_date_lot1 = Datetime.now() - timedelta(days=5)
         quant_lot1.in_date = initial_in_date_lot1
 
         # Move one quant to pack location
@@ -3626,8 +3627,7 @@ def test_in_date_2(self):
         # As lot1 has an older date and FIFO is set by default, it's the one that should be
         # in pack.
         self.assertEqual(len(quant_in_pack), 1)
-        from odoo.fields import Datetime
-        self.assertEqual(quant_in_pack.in_date, Datetime.to_string(initial_in_date_lot1))
+        self.assertAlmostEqual(quant_in_pack.in_date, initial_in_date_lot1, delta=timedelta(seconds=1))
         self.assertEqual(quant_in_pack.lot_id, lot1)
 
         # Now, edit the move line and actually move the other lot
@@ -3640,7 +3640,7 @@ def test_in_date_2(self):
             ('lot_id', '=', lot1.id),
         ])
         self.assertEqual(quant_lot1.location_id, self.stock_location)
-        self.assertEqual(quant_lot1.in_date, Datetime.to_string(initial_in_date_lot1))
+        self.assertAlmostEqual(quant_lot1.in_date, initial_in_date_lot1, delta=timedelta(seconds=1))
 
         # Check that lo2 is in pack with is right in_date
         quant_lot2 = self.env['stock.quant'].search([
@@ -3649,7 +3649,7 @@ def test_in_date_2(self):
             ('lot_id', '=', lot2.id),
         ])
         self.assertEqual(quant_lot2.location_id, self.pack_location)
-        self.assertEqual(quant_lot2.in_date, initial_in_date_lot2)
+        self.assertAlmostEqual(quant_lot2.in_date, initial_in_date_lot2, delta=timedelta(seconds=1))
 
     def test_in_date_3(self):
         """ Check that, when creating a move line on a done stock move, the lot and its incoming
@@ -3707,8 +3707,9 @@ def test_in_date_3(self):
             ('product_id', '=', self.product3.id),
             ('lot_id', '=', lot1.id),
         ])
-        from datetime import datetime, timedelta
-        initial_in_date_lot1 = datetime.now() - timedelta(days=5)
+        from odoo.fields import Datetime
+        from datetime import timedelta
+        initial_in_date_lot1 = Datetime.now() - timedelta(days=5)
         quant_lot1.in_date = initial_in_date_lot1
 
         # Move one quant to pack location
@@ -3741,12 +3742,11 @@ def test_in_date_3(self):
             ('product_id', '=', self.product3.id),
         ])
         self.assertEqual(len(quants), 2)
-        from odoo.fields import Datetime
         for quant in quants:
             if quant.lot_id == lot1:
-                self.assertEqual(quant.in_date, Datetime.to_string(initial_in_date_lot1))
+                self.assertAlmostEqual(quant.in_date, initial_in_date_lot1, delta=timedelta(seconds=1))
             elif quant.lot_id == lot2:
-                self.assertEqual(quant.in_date, initial_in_date_lot2)
+                self.assertAlmostEqual(quant.in_date, initial_in_date_lot2, delta=timedelta(seconds=1))
 
     def test_transit_1(self):
         """ Receive some products, send some to transit, check the product's `available_qty`
diff --git a/addons/stock/tests/test_quant.py b/addons/stock/tests/test_quant.py
index 9fb150341669d..749c10e57e3f1 100644
--- a/addons/stock/tests/test_quant.py
+++ b/addons/stock/tests/test_quant.py
@@ -763,7 +763,8 @@ def test_in_date_5(self):
             'product_id': product1.id,
         })
 
-        in_date1 = datetime.now()
+        from odoo.fields import Datetime
+        in_date1 = Datetime.now()
         self.env['stock.quant']._update_available_quantity(product1, stock_location, 1.0, lot_id=lot1, in_date=in_date1)
 
         quant = self.env['stock.quant'].search([
@@ -773,10 +774,9 @@ def test_in_date_5(self):
         self.assertEqual(len(quant), 1)
         self.assertEqual(quant.quantity, 1)
         self.assertEqual(quant.lot_id.id, lot1.id)
-        from odoo.fields import Datetime
-        self.assertEqual(quant.in_date, Datetime.to_string(in_date1))
+        self.assertEqual(quant.in_date, in_date1)
 
-        in_date2 = datetime.now() - timedelta(days=5)
+        in_date2 = Datetime.now() - timedelta(days=5)
         self.env['stock.quant']._update_available_quantity(product1, stock_location, 1.0, lot_id=lot1, in_date=in_date2)
 
         quant = self.env['stock.quant'].search([
@@ -786,4 +786,4 @@ def test_in_date_5(self):
         self.assertEqual(len(quant), 1)
         self.assertEqual(quant.quantity, 2)
         self.assertEqual(quant.lot_id.id, lot1.id)
-        self.assertEqual(quant.in_date, Datetime.to_string(in_date2))
+        self.assertEqual(quant.in_date, in_date2)
diff --git a/addons/stock_account/tests/test_stockvaluation.py b/addons/stock_account/tests/test_stockvaluation.py
index 200e91af00b5f..df22e8a382f48 100644
--- a/addons/stock_account/tests/test_stockvaluation.py
+++ b/addons/stock_account/tests/test_stockvaluation.py
@@ -4,7 +4,7 @@
 from datetime import timedelta
 
 from odoo.exceptions import UserError
-from odoo.fields import Date
+from odoo.fields import Date, Datetime
 from odoo.tests.common import TransactionCase
 
 
@@ -3260,7 +3260,7 @@ def test_move_in_or_out(self):
     def test_at_date_standard_1(self):
         self.product1.product_tmpl_id.cost_method = 'standard'
 
-        now = Date.from_string(Date.today())
+        now = Datetime.now()
         date1 = now - timedelta(days=8)
         date2 = now - timedelta(days=7)
         date3 = now - timedelta(days=6)
@@ -3387,42 +3387,42 @@ def test_at_date_standard_1(self):
         self.assertEqual(self.product1.stock_value, 712.5)
 
         # Quantity available at date
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date1)).qty_available, 0)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date2)).qty_available, 10)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date3)).qty_available, 30)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date4)).qty_available, 15)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date5)).qty_available, 15)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date6)).qty_available, -5)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date7)).qty_available, -5)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date8)).qty_available, 95)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date1)).qty_available, 0)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date2)).qty_available, 10)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date3)).qty_available, 30)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date4)).qty_available, 15)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date5)).qty_available, 15)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date6)).qty_available, -5)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date7)).qty_available, -5)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date8)).qty_available, 95)
 
         # Valuation at date
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date2)).stock_value, 100)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date3)).stock_value, 300)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date4)).stock_value, 150)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date5)).stock_value, 75)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date6)).stock_value, -25)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date8)).stock_value, 712.5)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date2)).stock_value, 100)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date3)).stock_value, 300)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date4)).stock_value, 150)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date5)).stock_value, 75)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date6)).stock_value, -25)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date8)).stock_value, 712.5)
 
         # Quantity at date
-        self.assertAlmostEqual(self.product1.with_context(to_date=Date.to_string(date1)).qty_at_date, 0.0)
-        self.assertAlmostEqual(self.product1.with_context(to_date=Date.to_string(date2)).qty_at_date, 10.0)
-        self.assertAlmostEqual(self.product1.with_context(to_date=Date.to_string(date3)).qty_at_date, 30.0)
-        self.assertAlmostEqual(self.product1.with_context(to_date=Date.to_string(date4)).qty_at_date, 15.0)
-        self.assertAlmostEqual(self.product1.with_context(to_date=Date.to_string(date5)).qty_at_date, 15.0)
-        self.assertAlmostEqual(self.product1.with_context(to_date=Date.to_string(date6)).qty_at_date, -5.0)
-        self.assertAlmostEqual(self.product1.with_context(to_date=Date.to_string(date7)).qty_at_date, -5.0)
-        self.assertAlmostEqual(self.product1.with_context(to_date=Date.to_string(date8)).qty_at_date, 95.0)
+        self.assertAlmostEqual(self.product1.with_context(to_date=Datetime.to_string(date1)).qty_at_date, 0.0)
+        self.assertAlmostEqual(self.product1.with_context(to_date=Datetime.to_string(date2)).qty_at_date, 10.0)
+        self.assertAlmostEqual(self.product1.with_context(to_date=Datetime.to_string(date3)).qty_at_date, 30.0)
+        self.assertAlmostEqual(self.product1.with_context(to_date=Datetime.to_string(date4)).qty_at_date, 15.0)
+        self.assertAlmostEqual(self.product1.with_context(to_date=Datetime.to_string(date5)).qty_at_date, 15.0)
+        self.assertAlmostEqual(self.product1.with_context(to_date=Datetime.to_string(date6)).qty_at_date, -5.0)
+        self.assertAlmostEqual(self.product1.with_context(to_date=Datetime.to_string(date7)).qty_at_date, -5.0)
+        self.assertAlmostEqual(self.product1.with_context(to_date=Datetime.to_string(date8)).qty_at_date, 95.0)
 
         # edit the done quantity of move1, decrease it
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date2)).qty_available, 10)
-        self.assertAlmostEqual(self.product1.with_context(to_date=Date.to_string(date2)).qty_at_date, 10.0)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date2)).qty_available, 10)
+        self.assertAlmostEqual(self.product1.with_context(to_date=Datetime.to_string(date2)).qty_at_date, 10.0)
         move1.quantity_done = 5
         move1.account_move_ids.write({'date': date2})
 
         # the quantity at date will reflect the change directly
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date2)).qty_available, 5)
-        self.assertAlmostEqual(self.product1.with_context(to_date=Date.to_string(date2)).qty_at_date, 5.0)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date2)).qty_available, 5)
+        self.assertAlmostEqual(self.product1.with_context(to_date=Datetime.to_string(date2)).qty_at_date, 5.0)
 
         # as when we decrease a quantity on a recreipt, we consider it as a out move with the price
         # of today, the value will be decrease of 100 - (5*7.5)
@@ -3430,22 +3430,22 @@ def test_at_date_standard_1(self):
 
         # the valuatin at date will take the qty at date * the standard price at date, that's why
         # it is different.
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date2)).stock_value, 50)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date2)).stock_value, 50)
 
         # edit move 4, send 15 instead of 20
         # we now have +5 + 20 - 15 -20 = -10 * a standard price of 5
-        self.assertAlmostEqual(self.product1.with_context(to_date=Date.to_string(date6)).qty_available, -10.0)
-        self.assertAlmostEqual(self.product1.with_context(to_date=Date.to_string(date6)).qty_at_date, -10.0)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date6)).stock_value, -50)
+        self.assertAlmostEqual(self.product1.with_context(to_date=Datetime.to_string(date6)).qty_available, -10.0)
+        self.assertAlmostEqual(self.product1.with_context(to_date=Datetime.to_string(date6)).qty_at_date, -10.0)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date6)).stock_value, -50)
         move4.quantity_done = 15
         move4.account_move_ids.write({'date': date6})
 
         # -(20*5) + (5*7.5)
         self.assertEqual(move4.value, -62.5)
         # we now have +5 + 20 - 15 -15 = -5 * a standard price of 5
-        self.assertAlmostEqual(self.product1.with_context(to_date=Date.to_string(date6)).qty_available, -5.0)
-        self.assertAlmostEqual(self.product1.with_context(to_date=Date.to_string(date6)).qty_at_date, -5.0)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date6)).stock_value, -25)
+        self.assertAlmostEqual(self.product1.with_context(to_date=Datetime.to_string(date6)).qty_available, -5.0)
+        self.assertAlmostEqual(self.product1.with_context(to_date=Datetime.to_string(date6)).qty_at_date, -5.0)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date6)).stock_value, -25)
 
     def test_at_date_fifo_1(self):
         """ Make some operations at different dates, check that the results of the valuation at
@@ -3454,7 +3454,7 @@ def test_at_date_fifo_1(self):
         """
         self.product1.product_tmpl_id.cost_method = 'fifo'
 
-        now = Date.from_string(Date.today())
+        now = Datetime.now()
         date1 = now - timedelta(days=8)
         date2 = now - timedelta(days=7)
         date3 = now - timedelta(days=6)
@@ -3580,18 +3580,18 @@ def test_at_date_fifo_1(self):
         # ending: manual valuation
         # ---------------------------------------------------------------------
         self.product1.product_tmpl_id.valuation = 'manual_periodic'
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date1)).qty_at_date, 20)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date1)).stock_value, 200)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date2)).qty_at_date, 30)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date2)).stock_value, 320)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date3)).qty_at_date, 15)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date3)).stock_value, 160)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date4)).qty_at_date, -5)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date4)).stock_value, -125)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date5)).qty_at_date, 95)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date5)).stock_value, 1375)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date6)).qty_at_date, 95)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date6)).stock_value, 1375)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date1)).qty_at_date, 20)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date1)).stock_value, 200)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date2)).qty_at_date, 30)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date2)).stock_value, 320)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date3)).qty_at_date, 15)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date3)).stock_value, 160)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date4)).qty_at_date, -5)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date4)).stock_value, -125)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date5)).qty_at_date, 95)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date5)).stock_value, 1375)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date6)).qty_at_date, 95)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date6)).stock_value, 1375)
         self.assertEqual(self.product1.qty_at_date, 95)
         self.assertEqual(self.product1.stock_value, 1375)
 
@@ -3599,25 +3599,25 @@ def test_at_date_fifo_1(self):
         # ending: perpetual valuation
         # ---------------------------------------------------------------------
         self.product1.product_tmpl_id.valuation = 'real_time'
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date1)).qty_at_date, 10)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date1)).stock_value, 100)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date2)).qty_at_date, 20)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date2)).stock_value, 220)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date3)).qty_at_date, 5)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date3)).stock_value, 60)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date4)).qty_at_date, -15)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date4)).stock_value, -180)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date5)).qty_at_date, 85)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date5)).stock_value, 1320)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date6)).qty_at_date, 85)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date6)).stock_value, 1275)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date1)).qty_at_date, 10)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date1)).stock_value, 100)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date2)).qty_at_date, 20)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date2)).stock_value, 220)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date3)).qty_at_date, 5)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date3)).stock_value, 60)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date4)).qty_at_date, -15)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date4)).stock_value, -180)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date5)).qty_at_date, 85)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date5)).stock_value, 1320)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date6)).qty_at_date, 85)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date6)).stock_value, 1275)
         self.assertEqual(self.product1.qty_at_date, 95)
         self.assertEqual(self.product1.stock_value, 1375)
 
     def test_at_date_fifo_2(self):
         self.product1.product_tmpl_id.cost_method = 'fifo'
 
-        now = Date.from_string(Date.today())
+        now = Datetime.now()
         date1 = now - timedelta(days=8)
         date2 = now - timedelta(days=7)
         date3 = now - timedelta(days=6)
@@ -3741,18 +3741,18 @@ def test_at_date_fifo_2(self):
         # ending: manual valuation
         # ---------------------------------------------------------------------
         self.product1.product_tmpl_id.valuation = 'manual_periodic'
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date1)).qty_at_date, 10)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date1)).stock_value, 100)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date2)).qty_at_date, 20)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date2)).stock_value, 250)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date3)).qty_at_date, -10)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date3)).stock_value, -200)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date4)).qty_at_date, 0)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date4)).stock_value, 0)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date5)).qty_at_date, 10)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date5)).stock_value, 100)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date6)).qty_at_date, 10)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date6)).stock_value, 100)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date1)).qty_at_date, 10)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date1)).stock_value, 100)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date2)).qty_at_date, 20)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date2)).stock_value, 250)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date3)).qty_at_date, -10)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date3)).stock_value, -200)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date4)).qty_at_date, 0)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date4)).stock_value, 0)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date5)).qty_at_date, 10)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date5)).stock_value, 100)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date6)).qty_at_date, 10)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date6)).stock_value, 100)
         self.assertEqual(self.product1.qty_at_date, 10)
         self.assertEqual(self.product1.stock_value, 100)
 
@@ -3760,17 +3760,17 @@ def test_at_date_fifo_2(self):
         # ending: perpetual valuation
         # ---------------------------------------------------------------------
         self.product1.product_tmpl_id.valuation = 'real_time'
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date1)).qty_at_date, 10)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date1)).stock_value, 100)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date2)).qty_at_date, 20)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date2)).stock_value, 250)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date3)).qty_at_date, -10)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date3)).stock_value, -150)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date4)).qty_at_date, 0)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date4)).stock_value, 50)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date5)).qty_at_date, 10)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date5)).stock_value, 150)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date6)).qty_at_date, 10)
-        self.assertEqual(self.product1.with_context(to_date=Date.to_string(date6)).stock_value, 100)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date1)).qty_at_date, 10)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date1)).stock_value, 100)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date2)).qty_at_date, 20)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date2)).stock_value, 250)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date3)).qty_at_date, -10)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date3)).stock_value, -150)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date4)).qty_at_date, 0)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date4)).stock_value, 50)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date5)).qty_at_date, 10)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date5)).stock_value, 150)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date6)).qty_at_date, 10)
+        self.assertEqual(self.product1.with_context(to_date=Datetime.to_string(date6)).stock_value, 100)
         self.assertEqual(self.product1.qty_at_date, 10)
         self.assertEqual(self.product1.stock_value, 100)
diff --git a/addons/stock_dropshipping/tests/test_lifo_price.py b/addons/stock_dropshipping/tests/test_lifo_price.py
index ea9c424435423..a93c1c1a4e003 100644
--- a/addons/stock_dropshipping/tests/test_lifo_price.py
+++ b/addons/stock_dropshipping/tests/test_lifo_price.py
@@ -86,7 +86,7 @@ def test_lifoprice(self):
         with out_form.move_ids_without_package.new() as move:
             move.product_id = product_lifo_icecream
             move.quantity_done = 20.0
-            move.date_expected = fields.Date.context_today(self.env['stock.move.line'])
+            move.date_expected = fields.Datetime.now()
         outgoing_lifo_shipment = out_form.save()
 
         # I assign this outgoing shipment
diff --git a/addons/web/models/ir_qweb.py b/addons/web/models/ir_qweb.py
index 757f30dc1e27e..34d2ecb0d5dd5 100644
--- a/addons/web/models/ir_qweb.py
+++ b/addons/web/models/ir_qweb.py
@@ -41,7 +41,7 @@ def record_to_html(self, record, field_name, options):
             if max_width or max_height:
                 max_size = '%sx%s' % (max_width, max_height)
 
-        sha = hashlib.sha1(getattr(record, '__last_update').encode('utf-8')).hexdigest()[0:7]
+        sha = hashlib.sha1(str(getattr(record, '__last_update')).encode('utf-8')).hexdigest()[0:7]
         max_size = '' if max_size is None else '/%s' % max_size
         avoid_if_small = '&avoid_if_small=true' if options.get('avoid_if_small') else ''
         src = '/web/image/%s/%s/%s%s?unique=%s%s' % (record._name, record.id, field_name, max_size, sha, avoid_if_small)
diff --git a/addons/website/models/website.py b/addons/website/models/website.py
index 40c1ce0ae6eba..819d4777cdd91 100644
--- a/addons/website/models/website.py
+++ b/addons/website/models/website.py
@@ -540,7 +540,7 @@ def enumerate_pages(self, query_string=None, force=False):
             if page.view_id and page.view_id.priority != 16:
                 record['__priority'] = min(round(page.view_id.priority / 32.0, 1), 1)
             if page['write_date']:
-                record['__lastmod'] = page['write_date'][:10]
+                record['__lastmod'] = page['write_date'].date()
             yield record
 
     @api.multi
@@ -563,7 +563,7 @@ def search_pages(self, needle=None, limit=None):
     def image_url(self, record, field, size=None):
         """ Returns a local url that points to the image field of a given browse record. """
         sudo_record = record.sudo()
-        sha = hashlib.sha1(getattr(sudo_record, '__last_update').encode('utf-8')).hexdigest()[0:7]
+        sha = hashlib.sha1(str(getattr(sudo_record, '__last_update')).encode('utf-8')).hexdigest()[0:7]
         size = '' if size is None else '/%s' % size
         return '/web/image/%s/%s/%s%s?unique=%s' % (record._name, record.id, field, size, sha)
 
diff --git a/addons/website_blog/models/website_blog.py b/addons/website_blog/models/website_blog.py
index 3741ee16035f7..6ff422579fd60 100644
--- a/addons/website_blog/models/website_blog.py
+++ b/addons/website_blog/models/website_blog.py
@@ -221,7 +221,8 @@ def write(self, vals):
         result = True
         for post in self:
             copy_vals = dict(vals)
-            if 'website_published' in vals and 'published_date' not in vals and (post.published_date or '') <= fields.Datetime.now():
+            if ('website_published' in vals and 'published_date' not in vals and
+                    (not post.published_date or post.published_date <= fields.Datetime.now())):
                 copy_vals['published_date'] = vals['website_published'] and fields.Datetime.now() or False
             result &= super(BlogPost, self).write(copy_vals)
         self._check_for_publication(vals)
diff --git a/addons/website_blog/views/website_blog_templates.xml b/addons/website_blog/views/website_blog_templates.xml
index 248cd5dec155d..44d1d4a9ffa85 100644
--- a/addons/website_blog/views/website_blog_templates.xml
+++ b/addons/website_blog/views/website_blog_templates.xml
@@ -562,14 +562,14 @@
     <title t-esc="blog.name"/>
     <link t-att-href="'%s/blog/%s' % (base_url ,blog.id)"/>
     <id t-esc="'%s/blog/%s' % (base_url, blog.id)"/>
-    <updated t-esc="(posts[0] if posts else blog).post_date.replace(' ', 'T') + 'Z'"/>
+    <updated t-esc="str((posts[0] if posts else blog).post_date).replace(' ', 'T') + 'Z'"/>
     <entry t-foreach="posts" t-as="post">
         <title t-esc="post.name"/>
         <link t-att-href="'%s%s' % (base_url, post.website_url)"/>
         <id t-esc="'%s%s' % (base_url, post.website_url)"/>
         <author><name t-esc="post.sudo().author_id.name"/></author>
         <summary t-esc="html2plaintext(post.teaser)"/>
-        <updated t-esc="post.post_date.replace(' ', 'T') + 'Z'"/>
+        <updated t-esc="str(post.post_date).replace(' ', 'T') + 'Z'"/>
     </entry>
 </feed>
 </template>
diff --git a/addons/website_event/models/event.py b/addons/website_event/models/event.py
index ac3eb999efe3c..f82baa954560a 100644
--- a/addons/website_event/models/event.py
+++ b/addons/website_event/models/event.py
@@ -150,7 +150,7 @@ def _get_ics_file(self):
 
             if not event.date_begin or not event.date_end:
                 raise UserError(_("No date has been specified for the event, no file will be generated."))
-            cal_event.add('created').value = fields.Datetime.from_string(fields.Datetime.now()).replace(tzinfo=pytz.timezone('UTC'))
+            cal_event.add('created').value = fields.Datetime.now().replace(tzinfo=pytz.timezone('UTC'))
             cal_event.add('dtstart').value = fields.Datetime.from_string(event.date_begin).replace(tzinfo=pytz.timezone('UTC'))
             cal_event.add('dtend').value = fields.Datetime.from_string(event.date_end).replace(tzinfo=pytz.timezone('UTC'))
             cal_event.add('summary').value = event.name
diff --git a/addons/website_forum/controllers/main.py b/addons/website_forum/controllers/main.py
index 4e493e5017ea4..c45e7a2e30a1a 100644
--- a/addons/website_forum/controllers/main.py
+++ b/addons/website_forum/controllers/main.py
@@ -256,7 +256,7 @@ def question(self, forum, question, **post):
         values.update({
             'main_object': question,
             'question': question,
-            'can_bump': (question.forum_id.allow_bump and not question.child_ids and (datetime.today() - datetime.strptime(question.write_date, tools.DEFAULT_SERVER_DATETIME_FORMAT)).days > 9),
+            'can_bump': (question.forum_id.allow_bump and not question.child_ids and (datetime.today() - question.write_date).days > 9),
             'header': {'question_data': True},
             'filters': filters,
             'reversed': reversed,
diff --git a/addons/website_forum/models/forum.py b/addons/website_forum/models/forum.py
index 8b5ed94091a60..74af33b462cc3 100644
--- a/addons/website_forum/models/forum.py
+++ b/addons/website_forum/models/forum.py
@@ -312,7 +312,7 @@ def _get_plain_content(self):
     @api.depends('vote_count', 'forum_id.relevancy_post_vote', 'forum_id.relevancy_time_decay')
     def _compute_relevancy(self):
         if self.create_date:
-            days = (datetime.today() - datetime.strptime(self.create_date, tools.DEFAULT_SERVER_DATETIME_FORMAT)).days
+            days = (datetime.today() - self.create_date).days
             self.relevancy = math.copysign(1, self.vote_count) * (abs(self.vote_count - 1) ** self.forum_id.relevancy_post_vote / (days + 2) ** self.forum_id.relevancy_time_decay)
         else:
             self.relevancy = 0
diff --git a/addons/website_sale/models/sale_order.py b/addons/website_sale/models/sale_order.py
index 45f36c11dbde0..098edad13783e 100644
--- a/addons/website_sale/models/sale_order.py
+++ b/addons/website_sale/models/sale_order.py
@@ -47,7 +47,7 @@ def _compute_cart_info(self):
     @api.depends('team_id.team_type', 'date_order', 'order_line', 'state', 'partner_id')
     def _compute_abandoned_cart(self):
         abandoned_delay = float(self.env['ir.config_parameter'].sudo().get_param('website_sale.cart_abandoned_delay', '1.0'))
-        abandoned_datetime = fields.Datetime.to_string(datetime.utcnow() - relativedelta(hours=abandoned_delay))
+        abandoned_datetime = datetime.utcnow() - relativedelta(hours=abandoned_delay)
         for order in self:
             domain = order.date_order <= abandoned_datetime and order.team_id.team_type == 'website' and order.state == 'draft' and order.partner_id.id != self.env.ref('base.public_partner').id and order.order_line
             order.is_abandoned_cart = bool(domain)
diff --git a/addons/website_sale/views/templates.xml b/addons/website_sale/views/templates.xml
index 78322a9805d78..9c42b6698d797 100644
--- a/addons/website_sale/views/templates.xml
+++ b/addons/website_sale/views/templates.xml
@@ -429,7 +429,7 @@
                             <div id="o-carousel-product" class="carousel slide" data-ride="carousel" data-interval="0">
                               <div class="carousel-outer">
                                 <div class="carousel-inner">
-                                    <div t-if="variant_img" class="carousel-item active" itemprop="image" t-field="product[:1].product_variant_id.image" t-options="{'widget': 'image', 'class': 'product_detail_img js_variant_img', 'alt-field': 'name', 'zoom': 'image', 'unique': product['__last_update'] + (product.product_variant_id['__last_update'] or '')}"/>
+                                    <div t-if="variant_img" class="carousel-item active" itemprop="image" t-field="product[:1].product_variant_id.image" t-options="{'widget': 'image', 'class': 'product_detail_img js_variant_img', 'alt-field': 'name', 'zoom': 'image', 'unique': str(product['__last_update']) + (str(product.product_variant_id['__last_update']) or '')}"/>
                                     <div t-attf-class="carousel-item#{'' if variant_img else ' active'}" itemprop="image" t-field="product.image" t-options="{'widget': 'image', 'class': 'product_detail_img', 'alt-field': 'name', 'zoom': 'image', 'unique': product['__last_update']}"/>
                                     <t t-if="len(image_ids)" t-foreach="image_ids" t-as="pimg">
                                         <div class="carousel-item" t-field="pimg.image" t-options='{"widget": "image", "class": "product_detail_img", "alt-field": "name", "zoom": "image" }'/>
diff --git a/doc/reference/orm.rst b/doc/reference/orm.rst
index 9ce03c8709a2e..1a0dba9edf1e3 100644
--- a/doc/reference/orm.rst
+++ b/doc/reference/orm.rst
@@ -866,13 +866,57 @@ Basic fields
 .. autoclass:: odoo.fields.Html
     :show-inheritance:
 
+.. _reference/orm/fields/date_datetime:
+
+Date and Datetime fields
+------------------------
+
+Dates and Datetimes are very important fields in any kind of business
+application, they are heavily used in many popular Odoo applications such as
+logistics or accounting and their misuse can create invisible yet painful
+bugs, this excerpt aims to provide Odoo developers with the knowledge required
+to avoid misusing these fields.
+
+When assigning a value to a Date/Datetime field, the following options are valid:
+    * A string in the proper server format **(YYYY-MM-DD)** for Date fields,
+      **(YYYY-MM-DD HH:MM:SS)** for Datetime fields.
+    * A `date` or `datetime` object.
+    * `False` or `None`.
+
+If not sure of the type of the value being assigned to a Date/Datetime object,
+the best course of action is to pass the value to
+:func:`~odoo.fields.Date.to_date` or :func:`~odoo.fields.Datetime.to_datetime`
+which will attempt to convert the value to a date or datetime object
+respectively, which can then be assigned to the field in question.
+
+.. admonition:: Example
+
+    To parse date/datetimes coming from external sources::
+
+        fields.Date.to_date(self._context.get('date_from'))
+
+Date / Datetime comparison best practices:
+    * Date fields can **only** be compared to date objects.
+    * Datetime fields can **only** be compared to datetime objects.
+
+    .. warning:: Strings representing dates and datetimes can be compared
+                 between each other, however the result may not be the expected
+                 result, as a datetime string will always be greater than a
+                 date string, therefore this practice is **heavily**
+                 discouraged.
+
+Common operations with dates and datetimes such as addition, substraction or
+fetching the start/end of a period are exposed through both
+:class:`~odoo.fields.Date` and :class:`~odoo.fields.Datetime`.
+These helpers are also available by importing `odoo.tools.date_utils`.
+
 .. autoclass:: odoo.fields.Date
     :show-inheritance:
-    :members: today, context_today, from_string, to_string
+    :members: today, context_today, to_date, to_string, start_of, end_of, add, subtract
 
 .. autoclass:: odoo.fields.Datetime
     :show-inheritance:
-    :members: now, context_timestamp, from_string, to_string
+    :members: now, today, context_timestamp, to_datetime, to_string, start_of, end_of, add, subtract
 
 .. _reference/orm/fields/relational:
 
diff --git a/odoo/addons/base/models/assetsbundle.py b/odoo/addons/base/models/assetsbundle.py
index d60cfe3475394..345ab279e32fc 100644
--- a/odoo/addons/base/models/assetsbundle.py
+++ b/odoo/addons/base/models/assetsbundle.py
@@ -358,7 +358,7 @@ def is_css_preprocessed(self):
                 attachments = self.env['ir.attachment'].sudo().search(assets_domain)
                 for attachment in attachments:
                     asset = assets[attachment.url]
-                    if asset.last_modified > fields.Datetime.from_string(attachment['__last_update']):
+                    if asset.last_modified > attachment['__last_update']:
                         outdated = True
                         break
                     if asset._content is None:
@@ -539,12 +539,7 @@ def last_modified(self):
             if self._filename:
                 return datetime.fromtimestamp(os.path.getmtime(self._filename))
             elif self._ir_attach:
-                server_format = tools.DEFAULT_SERVER_DATETIME_FORMAT
-                last_update = self._ir_attach['__last_update']
-                try:
-                    return datetime.strptime(last_update, server_format + '.%f')
-                except ValueError:
-                    return datetime.strptime(last_update, server_format)
+                return self._ir_attach['__last_update']
         except Exception:
             pass
         return datetime(1970, 1, 1)
diff --git a/odoo/addons/base/models/ir_http.py b/odoo/addons/base/models/ir_http.py
index 6fab91e749812..eea8c78927a31 100644
--- a/odoo/addons/base/models/ir_http.py
+++ b/odoo/addons/base/models/ir_http.py
@@ -139,12 +139,7 @@ def _serve_attachment(cls):
                 return werkzeug.utils.redirect(name, 301)
 
             response = werkzeug.wrappers.Response()
-            server_format = tools.DEFAULT_SERVER_DATETIME_FORMAT
-            try:
-                response.last_modified = datetime.datetime.strptime(wdate, server_format + '.%f')
-            except ValueError:
-                # just in case we have a timestamp without microseconds
-                response.last_modified = datetime.datetime.strptime(wdate, server_format)
+            response.last_modified = wdate
 
             response.set_etag(checksum)
             response.make_conditional(request.httprequest)
diff --git a/odoo/addons/base/models/ir_sequence.py b/odoo/addons/base/models/ir_sequence.py
index 6a23b0e3f0003..b096e65e591cc 100644
--- a/odoo/addons/base/models/ir_sequence.py
+++ b/odoo/addons/base/models/ir_sequence.py
@@ -196,9 +196,9 @@ def _interpolate(s, d):
         def _interpolation_dict():
             now = range_date = effective_date = datetime.now(pytz.timezone(self._context.get('tz') or 'UTC'))
             if self._context.get('ir_sequence_date'):
-                effective_date = datetime.strptime(self._context.get('ir_sequence_date'), '%Y-%m-%d')
+                effective_date = fields.Datetime.from_string(self._context.get('ir_sequence_date'))
             if self._context.get('ir_sequence_date_range'):
-                range_date = datetime.strptime(self._context.get('ir_sequence_date_range'), '%Y-%m-%d')
+                range_date = fields.Datetime.from_string(self._context.get('ir_sequence_date_range'))
 
             sequences = {
                 'year': '%Y', 'month': '%m', 'day': '%d', 'y': '%y', 'doy': '%j', 'woy': '%W',
@@ -230,12 +230,10 @@ def _create_date_range_seq(self, date):
         date_to = '{}-12-31'.format(year)
         date_range = self.env['ir.sequence.date_range'].search([('sequence_id', '=', self.id), ('date_from', '>=', date), ('date_from', '<=', date_to)], order='date_from desc', limit=1)
         if date_range:
-            date_to = datetime.strptime(date_range.date_from, '%Y-%m-%d') + timedelta(days=-1)
-            date_to = date_to.strftime('%Y-%m-%d')
+            date_to = date_range.date_from + timedelta(days=-1)
         date_range = self.env['ir.sequence.date_range'].search([('sequence_id', '=', self.id), ('date_to', '>=', date_from), ('date_to', '<=', date)], order='date_to desc', limit=1)
         if date_range:
-            date_from = datetime.strptime(date_range.date_to, '%Y-%m-%d') + timedelta(days=1)
-            date_from = date_from.strftime('%Y-%m-%d')
+            date_from = date_range.date_to + timedelta(days=1)
         seq_date_range = self.env['ir.sequence.date_range'].sudo().create({
             'date_from': date_from,
             'date_to': date_to,
diff --git a/odoo/addons/base/tests/test_ir_sequence_date_range.py b/odoo/addons/base/tests/test_ir_sequence_date_range.py
index 7bd43eb4ea99f..08729f3a07254 100644
--- a/odoo/addons/base/tests/test_ir_sequence_date_range.py
+++ b/odoo/addons/base/tests/test_ir_sequence_date_range.py
@@ -22,7 +22,7 @@ def test_ir_sequence_date_range_1_create(self):
     def test_ir_sequence_date_range_2_change_dates(self):
         """ Draw numbers to create a first subsequence then change its date range. Then, try to draw a new number adn check a new subsequence was correctly created. """
         year = date.today().year - 1
-        january = lambda d: date(year, 1, d).strftime(DATE_FORMAT)
+        january = lambda d: date(year, 1, d)
 
         seq16 = self.env['ir.sequence'].with_context({'ir_sequence_date': january(16)})
         n = seq16.next_by_code('test_sequence_date_range')
@@ -63,7 +63,7 @@ def test_ir_sequence_date_range_1_create_no_gap(self):
     def test_ir_sequence_date_range_2_change_dates(self):
         """ Draw numbers to create a first subsequence then change its date range. Then, try to draw a new number adn check a new subsequence was correctly created. """
         year = date.today().year - 1
-        january = lambda d: date(year, 1, d).strftime(DATE_FORMAT)
+        january = lambda d: date(year, 1, d)
 
         seq16 = self.env['ir.sequence'].with_context({'ir_sequence_date': january(16)})
         n = seq16.next_by_code('test_sequence_date_range_2')
@@ -111,7 +111,7 @@ def test_ir_sequence_date_range_1_create(self):
     def test_ir_sequence_date_range_2_use(self):
         """ Make some use of the sequences to create some subsequences """
         year = date.today().year - 1
-        january = lambda d: date(year, 1, d).strftime(DATE_FORMAT)
+        january = lambda d: date(year, 1, d)
 
         seq = self.env['ir.sequence']
         seq16 = self.env['ir.sequence'].with_context({'ir_sequence_date': january(16)})
diff --git a/odoo/addons/test_impex/tests/test_load.py b/odoo/addons/test_impex/tests/test_load.py
index 628e879374d70..5a29ec9e1c5b8 100644
--- a/odoo/addons/test_impex/tests/test_load.py
+++ b/odoo/addons/test_impex/tests/test_load.py
@@ -5,6 +5,7 @@
 import pkgutil
 import re
 
+from odoo import fields
 from odoo.tests import common
 from odoo.tools.misc import mute_logger
 
@@ -1065,7 +1066,7 @@ def test_checktz1(self):
             ['value'], [['2012-02-03 11:11:11']], {'tz': 'Pacific/Kiritimati'})
         self.assertFalse(result['messages'])
         self.assertEqual(
-            values(self.read(domain=[('id', 'in', result['ids'])])),
+            [fields.Datetime.to_string(value['value']) for value in self.read(domain=[('id', 'in', result['ids'])])],
             ['2012-02-02 21:11:11'])
 
         # UTC-0930
@@ -1073,7 +1074,7 @@ def test_checktz1(self):
             ['value'], [['2012-02-03 11:11:11']], {'tz': 'Pacific/Marquesas'})
         self.assertFalse(result['messages'])
         self.assertEqual(
-            values(self.read(domain=[('id', 'in', result['ids'])])),
+            [fields.Datetime.to_string(value['value']) for value in self.read(domain=[('id', 'in', result['ids'])])],
             ['2012-02-03 20:41:11'])
 
     def test_usertz(self):
@@ -1087,7 +1088,7 @@ def test_usertz(self):
             ['value'], [['2012-02-03 11:11:11']])
         self.assertFalse(result['messages'])
         self.assertEqual(
-            values(self.read(domain=[('id', 'in', result['ids'])])),
+            [fields.Datetime.to_string(value['value']) for value in self.read(domain=[('id', 'in', result['ids'])])],
             ['2012-02-03 01:11:11'])
 
     def test_notz(self):
@@ -1099,7 +1100,7 @@ def test_notz(self):
         result = self.import_(['value'], [['2012-02-03 11:11:11']])
         self.assertFalse(result['messages'])
         self.assertEqual(
-            values(self.read(domain=[('id', 'in', result['ids'])])),
+            [fields.Datetime.to_string(value['value']) for value in self.read(domain=[('id', 'in', result['ids'])])],
             ['2012-02-03 11:11:11'])
 
 
diff --git a/odoo/addons/test_new_api/tests/test_new_fields.py b/odoo/addons/test_new_api/tests/test_new_fields.py
index 1b458fa604d91..b4459f298ff89 100644
--- a/odoo/addons/test_new_api/tests/test_new_fields.py
+++ b/odoo/addons/test_new_api/tests/test_new_fields.py
@@ -1,11 +1,13 @@
 #
 # test cases for new-style fields
 #
-from datetime import date, datetime
+from datetime import date, datetime, time
 
-from odoo.exceptions import AccessError, UserError, except_orm
+from odoo import fields
+from odoo.exceptions import AccessError, UserError
 from odoo.tests import common
 from odoo.tools import mute_logger, float_repr, pycompat
+from odoo.tools.date_utils import add, subtract, start_of, end_of
 
 
 class TestFields(common.TransactionCase):
@@ -484,20 +486,117 @@ def test_21_date(self):
         record.date = None
         self.assertFalse(record.date)
 
-        # one may assign date and datetime objects
+        # one may assign date but not datetime objects
         record.date = date(2012, 5, 1)
-        self.assertEqual(record.date, '2012-05-01')
+        self.assertEqual(record.date, date(2012, 5, 1))
 
-        record.date = datetime(2012, 5, 1, 10, 45, 00)
-        self.assertEqual(record.date, '2012-05-01')
+        with self.assertRaises(TypeError):
+            record.date = datetime(2012, 5, 1, 10, 45, 0)
 
-        # one may assign dates in the default format, and it must be checked
+        # one may assign dates and datetime in the default format, and it must be checked
         record.date = '2012-05-01'
-        self.assertEqual(record.date, '2012-05-01')
+        self.assertEqual(record.date, date(2012, 5, 1))
+
+        record.date = "2012-05-01 10:45:00"
+        self.assertEqual(record.date, date(2012, 5, 1))
 
         with self.assertRaises(ValueError):
             record.date = '12-5-1'
 
+        for i in range(0, 10):
+            self.assertEqual(fields.Datetime.now().microsecond, 0)
+
+    def test_21_date_datetime_helpers(self):
+        """ test date/datetime fields helpers """
+        _date = fields.Date.from_string("2077-10-23")
+        _datetime = fields.Datetime.from_string("2077-10-23 09:42:00")
+
+        # addition
+        self.assertEqual(add(_date, days=5), date(2077, 10, 28))
+        self.assertEqual(add(_datetime, seconds=10), datetime(2077, 10, 23, 9, 42, 10))
+
+        # subtraction
+        self.assertEqual(subtract(_date, months=1), date(2077, 9, 23))
+        self.assertEqual(subtract(_datetime, hours=2), datetime(2077, 10, 23, 7, 42, 0))
+
+        # start_of
+        # year
+        self.assertEqual(start_of(_date, 'year'), date(2077, 1, 1))
+        self.assertEqual(start_of(_datetime, 'year'), datetime(2077, 1, 1))
+
+        # quarter
+        q1 = date(2077, 1, 1)
+        q2 = date(2077, 4, 1)
+        q3 = date(2077, 7, 1)
+        q4 = date(2077, 10, 1)
+        self.assertEqual(start_of(_date.replace(month=3), 'quarter'), q1)
+        self.assertEqual(start_of(_date.replace(month=5), 'quarter'), q2)
+        self.assertEqual(start_of(_date.replace(month=7), 'quarter'), q3)
+        self.assertEqual(start_of(_date, 'quarter'), q4)
+        self.assertEqual(start_of(_datetime, 'quarter'), datetime.combine(q4, time.min))
+
+        # month
+        self.assertEqual(start_of(_date, 'month'), date(2077, 10, 1))
+        self.assertEqual(start_of(_datetime, 'month'), datetime(2077, 10, 1))
+
+        # week
+        self.assertEqual(start_of(_date, 'week'), date(2077, 10, 18))
+        self.assertEqual(start_of(_datetime, 'week'), datetime(2077, 10, 18))
+
+        # day
+        self.assertEqual(start_of(_date, 'day'), _date)
+        self.assertEqual(start_of(_datetime, 'day'), _datetime.replace(hour=0, minute=0, second=0))
+
+        # hour
+        with self.assertRaises(ValueError):
+            start_of(_date, 'hour')
+        self.assertEqual(start_of(_datetime, 'hour'), _datetime.replace(minute=0, second=0))
+
+        # invalid
+        with self.assertRaises(ValueError):
+            start_of(_datetime, 'poop')
+
+        # end_of
+        # year
+        self.assertEqual(end_of(_date, 'year'), _date.replace(month=12, day=31))
+        self.assertEqual(end_of(_datetime, 'year'),
+                         datetime.combine(_date.replace(month=12, day=31), time.max))
+
+        # quarter
+        q1 = date(2077, 3, 31)
+        q2 = date(2077, 6, 30)
+        q3 = date(2077, 9, 30)
+        q4 = date(2077, 12, 31)
+        self.assertEqual(end_of(_date.replace(month=2), 'quarter'), q1)
+        self.assertEqual(end_of(_date.replace(month=4), 'quarter'), q2)
+        self.assertEqual(end_of(_date.replace(month=9), 'quarter'), q3)
+        self.assertEqual(end_of(_date, 'quarter'), q4)
+        self.assertEqual(end_of(_datetime, 'quarter'), datetime.combine(q4, time.max))
+
+        # month
+        self.assertEqual(end_of(_date, 'month'), _date.replace(day=31))
+        self.assertEqual(end_of(_datetime, 'month'),
+                         datetime.combine(date(2077, 10, 31), time.max))
+
+        # week
+        self.assertEqual(end_of(_date, 'week'), date(2077, 10, 24))
+        self.assertEqual(end_of(_datetime, 'week'),
+                         datetime.combine(datetime(2077, 10, 24), time.max))
+
+        # day
+        self.assertEqual(end_of(_date, 'day'), _date)
+        self.assertEqual(end_of(_datetime, 'day'), datetime.combine(_datetime, time.max))
+
+        # hour
+        with self.assertRaises(ValueError):
+            end_of(_date, 'hour')
+        self.assertEqual(end_of(_datetime, 'hour'),
+                         datetime.combine(_datetime, time.max).replace(hour=_datetime.hour))
+
+        # invalid
+        with self.assertRaises(ValueError):
+            end_of(_datetime, 'crap')
+
     def test_22_selection(self):
         """ test selection fields """
         record = self.env['test_new_api.mixed'].create({})
diff --git a/odoo/fields.py b/odoo/fields.py
index 0e7f53fe04cb3..ec3a16b0a7161 100644
--- a/odoo/fields.py
+++ b/odoo/fields.py
@@ -4,7 +4,8 @@
 """ High-level objects for fields. """
 
 from collections import OrderedDict, defaultdict
-from datetime import date, datetime
+from datetime import date, datetime, time
+from dateutil.relativedelta import relativedelta
 from functools import partial
 from operator import attrgetter
 import itertools
@@ -21,7 +22,8 @@
 import psycopg2
 
 from .sql_db import LazyCursor
-from .tools import float_repr, float_round, frozendict, html_sanitize, human_size, pg_varchar, ustr, OrderedSet, pycompat, sql
+from .tools import float_repr, float_round, frozendict, html_sanitize, human_size, pg_varchar,\
+    ustr, OrderedSet, pycompat, sql, date_utils
 from .tools import DEFAULT_SERVER_DATE_FORMAT as DATE_FORMAT
 from .tools import DEFAULT_SERVER_DATETIME_FORMAT as DATETIME_FORMAT
 from .tools.translate import html_translate, _
@@ -1516,23 +1518,30 @@ class Date(Field):
     column_type = ('date', 'date')
     column_cast_from = ('timestamp',)
 
+    start_of = staticmethod(date_utils.start_of)
+    end_of = staticmethod(date_utils.end_of)
+    add = staticmethod(date_utils.add)
+    subtract = staticmethod(date_utils.subtract)
+
     @staticmethod
     def today(*args):
         """ Return the current day in the format expected by the ORM.
             This function may be used to compute default values.
         """
-        return date.today().strftime(DATE_FORMAT)
+        return date.today()
 
     @staticmethod
     def context_today(record, timestamp=None):
-        """ Return the current date as seen in the client's timezone in a format
-            fit for date fields. This method may be used to compute default
-            values.
-
-            :param datetime timestamp: optional datetime value to use instead of
-                the current date and time (must be a datetime, regular dates
-                can't be converted between timezones.)
-            :rtype: str
+        """
+        Return the current date as seen in the client's timezone in a format
+        fit for date fields. This method may be used to compute default
+        values.
+
+        :param record: recordset from which the timezone will be obtained.
+        :param datetime timestamp: optional datetime value to use instead of
+            the current date and time (must be a datetime, regular dates
+            can't be converted between timezones).
+        :rtype: date
         """
         today = timestamp or datetime.now()
         context_today = None
@@ -1544,33 +1553,55 @@ def context_today(record, timestamp=None):
             except Exception:
                 _logger.debug("failed to compute context/client-specific today date, using UTC value for `today`",
                               exc_info=True)
-        return (context_today or today).strftime(DATE_FORMAT)
+        return (context_today or today).date()
 
     @staticmethod
-    def from_string(value):
-        """ Convert an ORM ``value`` into a :class:`date` value. """
+    def to_date(value):
+        """
+        Attempt to convert ``value`` to a :class:`date` object.
+
+        This function can take as input different kinds of types:
+            * A falsy object, in which case None will be returned.
+            * A string representing a date or datetime.
+            * A date object, in which case the object will be returned as-is.
+            * A datetime object, in which case it will be converted to a date object and all\
+                        datetime-specific information will be lost (HMS, TZ, ...).
+
+        :param value: value to convert.
+        :return: an object representing ``value``.
+        :rtype: date
+        """
         if not value:
             return None
+        if isinstance(value, date):
+            if isinstance(value, datetime):
+                return value.date()
+            return value
         value = value[:DATE_LENGTH]
         return datetime.strptime(value, DATE_FORMAT).date()
 
+    # kept for backwards compatibility, but consider `from_string` as deprecated, will probably
+    # be removed after V12
+    from_string = to_date
+
     @staticmethod
     def to_string(value):
-        """ Convert a :class:`date` value into the format expected by the ORM. """
-        return value.strftime(DATE_FORMAT) if value else False
+        """
+        Convert a :class:`date` or :class:`datetime` object to a string.
 
-    def convert_to_column(self, value, record, values=None, validate=True):
-        return super(Date, self).convert_to_column(value or None, record, values, validate)
+        :param value: value to convert.
+        :return: a string representing ``value`` in the server's date format, if ``value`` is of
+            type :class:`datetime`, the hours, minute, seconds, tzinfo will be truncated.
+        :rtype: str
+        """
+        return value.strftime(DATE_FORMAT) if value else False
 
     def convert_to_cache(self, value, record, validate=True):
         if not value:
             return False
-        if isinstance(value, pycompat.string_types):
-            if validate:
-                # force parsing for validation
-                self.from_string(value)
-            return value[:DATE_LENGTH]
-        return self.to_string(value)
+        if isinstance(value, datetime):
+            raise TypeError("%s (field %s) must be string or date, not datetime." % (value, self))
+        return self.from_string(value)
 
     def convert_to_export(self, value, record):
         if not value:
@@ -1583,26 +1614,40 @@ class Datetime(Field):
     column_type = ('timestamp', 'timestamp')
     column_cast_from = ('date',)
 
+    start_of = staticmethod(date_utils.start_of)
+    end_of = staticmethod(date_utils.end_of)
+    add = staticmethod(date_utils.add)
+    subtract = staticmethod(date_utils.subtract)
+
     @staticmethod
     def now(*args):
         """ Return the current day and time in the format expected by the ORM.
             This function may be used to compute default values.
         """
-        return datetime.now().strftime(DATETIME_FORMAT)
+        # microseconds must be annihilated as they don't comply with the server datetime format
+        return datetime.now().replace(microsecond=0)
+
+    @staticmethod
+    def today(*args):
+        """
+        Return the current day, at midnight (00:00:00).
+        """
+        return Datetime.now().replace(hour=0, minute=0, second=0)
 
     @staticmethod
     def context_timestamp(record, timestamp):
-        """Returns the given timestamp converted to the client's timezone.
-           This method is *not* meant for use as a default initializer,
-           because datetime fields are automatically converted upon
-           display on client side. For default values :meth:`fields.datetime.now`
-           should be used instead.
-
-           :param datetime timestamp: naive datetime value (expressed in UTC)
-                                      to be converted to the client timezone
-           :rtype: datetime
-           :return: timestamp converted to timezone-aware datetime in context
-                    timezone
+        """
+        Returns the given timestamp converted to the client's timezone.
+        This method is *not* meant for use as a default initializer,
+        because datetime fields are automatically converted upon
+        display on client side. For default values, :meth:`fields.Datetime.now`
+        should be used instead.
+
+        :param record: recordset from which the timezone will be obtained.
+        :param datetime timestamp: naive datetime value (expressed in UTC)
+            to be converted to the client timezone.
+        :rtype: datetime
+        :return: timestamp converted to timezone-aware datetime in context timezone.
         """
         assert isinstance(timestamp, datetime), 'Datetime instance expected'
         tz_name = record._context.get('tz') or record.env.user.tz
@@ -1618,35 +1663,53 @@ def context_timestamp(record, timestamp):
         return utc_timestamp
 
     @staticmethod
-    def from_string(value):
-        """ Convert an ORM ``value`` into a :class:`datetime` value. """
+    def to_datetime(value):
+        """
+        Convert an ORM ``value`` into a :class:`datetime` value.
+
+        This function can take as input different kinds of types:
+            * A falsy object, in which case None will be returned.
+            * A string representing a date or datetime.
+            * A datetime object, in which case the object will be returned as-is.
+            * A date object, in which case it will be converted to a datetime object.
+
+        :param value: value to convert.
+        :return: an object representing ``value``.
+        :rtype: datetime
+        """
         if not value:
             return None
-        value = value[:DATETIME_LENGTH]
-        if len(value) == DATE_LENGTH:
-            value += " 00:00:00"
-        return datetime.strptime(value, DATETIME_FORMAT)
+        if isinstance(value, date):
+            if isinstance(value, datetime):
+                return value
+            return datetime.combine(value, time.min)
+        try:
+            return datetime.strptime(value[:DATETIME_LENGTH], DATETIME_FORMAT)
+        except ValueError:
+            return datetime.strptime(value, DATE_FORMAT)
+
+    # kept for backwards compatibility, but consider `from_string` as deprecated, will probably
+    # be removed after V12
+    from_string = to_datetime
 
     @staticmethod
     def to_string(value):
-        """ Convert a :class:`datetime` value into the format expected by the ORM. """
-        return value.strftime(DATETIME_FORMAT) if value else False
+        """
+        Convert a :class:`datetime` or :class:`date` object to a string.
 
-    def convert_to_column(self, value, record, values=None, validate=True):
-        return super(Datetime, self).convert_to_column(value or None, record, values, validate)
+        :param value: value to convert.
+        :return: a string representing ``value`` in the server's datetime format, if ``value`` is
+            of type :class:`date`, the time portion will be midnight (00:00:00).
+        :rtype: str
+        """
+        return value.strftime(DATETIME_FORMAT) if value else False
 
     def convert_to_cache(self, value, record, validate=True):
         if not value:
             return False
-        if isinstance(value, pycompat.string_types):
-            if validate:
-                # force parsing for validation
-                self.from_string(value)
-            value = value[:DATETIME_LENGTH]
-            if len(value) == DATE_LENGTH:
-                value += " 00:00:00"
-            return value
-        return self.to_string(value)
+        if isinstance(value, date) and not isinstance(value, datetime):
+            raise TypeError("%s (field %s) must be string or datetime, not date." % (value, self))
+        return self.from_string(value)
 
     def convert_to_export(self, value, record):
         if not value:
diff --git a/odoo/http.py b/odoo/http.py
index d32b4caa5e303..3d0126dbc4290 100644
--- a/odoo/http.py
+++ b/odoo/http.py
@@ -25,6 +25,7 @@
 from zlib import adler32
 
 import babel.core
+from datetime import datetime, date
 import passlib.utils
 import psycopg2
 import json
@@ -44,10 +45,11 @@
     psutil = None
 
 import odoo
+from odoo import fields
 from .service.server import memory_info
 from .service import security, model as service_model
 from .tools.func import lazy_property
-from .tools import ustr, consteq, frozendict, pycompat, unique
+from .tools import ustr, consteq, frozendict, pycompat, unique, date_utils
 
 from .modules.module import module_manifest
 
@@ -617,6 +619,7 @@ def handler():
         self.context = self.params.pop('context', dict(self.session.context))
 
     def _json_response(self, result=None, error=None):
+
         response = {
             'jsonrpc': '2.0',
             'id': self.jsonrequest.get('id')
@@ -632,10 +635,10 @@ def _json_response(self, result=None, error=None):
             # We need then to manage http sessions manually.
             response['session_id'] = self.session.sid
             mime = 'application/javascript'
-            body = "%s(%s);" % (self.jsonp, json.dumps(response, default=ustr),)
+            body = "%s(%s);" % (self.jsonp, json.dumps(response, default=date_utils.json_default))
         else:
             mime = 'application/json'
-            body = json.dumps(response, default=ustr)
+            body = json.dumps(response, default=date_utils.json_default)
 
         return Response(
             body, status=error and error.pop('http_status', 200) or 200,
diff --git a/odoo/osv/expression.py b/odoo/osv/expression.py
index 68d19edf04656..483f325322c63 100644
--- a/odoo/osv/expression.py
+++ b/odoo/osv/expression.py
@@ -120,6 +120,7 @@
 from functools import partial
 from zlib import crc32
 
+from datetime import date, datetime, time
 import odoo.modules
 from odoo.tools import pycompat
 from ..models import MAGIC_COLUMNS, BaseModel
@@ -1095,12 +1096,22 @@ def _get_expression(comodel, left, right, operator):
             # -------------------------------------------------
 
             else:
-                if field.type == 'datetime' and right and len(right) == 10:
-                    if operator in ('>', '<='):
-                        right += ' 23:59:59'
+                if field.type == 'datetime' and right:
+                    if isinstance(right, pycompat.string_types) and len(right) == 10:
+                        if operator in ('>', '<='):
+                            right += ' 23:59:59'
+                        else:
+                            right += ' 00:00:00'
+                        push(create_substitution_leaf(leaf, (left, operator, right), model))
+                    elif isinstance(right, date) and not isinstance(right, datetime):
+                        if operator in ('>', '<='):
+                            right = datetime.combine(right, time.max)
+                        else:
+                            right = datetime.combine(right, time.min)
+                        push(create_substitution_leaf(leaf, (left, operator, right), model))
                     else:
-                        right += ' 00:00:00'
-                    push(create_substitution_leaf(leaf, (left, operator, right), model))
+                        push_result(leaf)
+
 
                 elif field.translate is True and right:
                     need_wildcard = operator in ('like', 'ilike', 'not like', 'not ilike')
diff --git a/odoo/sql_db.py b/odoo/sql_db.py
index 6d96fb8aa7412..ae1db0d64361d 100644
--- a/odoo/sql_db.py
+++ b/odoo/sql_db.py
@@ -26,12 +26,6 @@
 
 _logger = logging.getLogger(__name__)
 
-types_mapping = {
-    'date': (1082,),
-    'time': (1083,),
-    'datetime': (1114,),
-}
-
 def unbuffer(symb, cr):
     if symb is None:
         return None
@@ -42,8 +36,6 @@ def undecimalize(symb, cr):
         return None
     return float(symb)
 
-for name, typeoid in types_mapping.items():
-    psycopg2.extensions.register_type(psycopg2.extensions.new_type(typeoid, name, lambda x, cr: x))
 psycopg2.extensions.register_type(psycopg2.extensions.new_type((700, 701, 1700,), 'float', undecimalize))
 
 
diff --git a/odoo/tools/date_utils.py b/odoo/tools/date_utils.py
index 76b19c2cf5501..e7d1aa24ffddc 100644
--- a/odoo/tools/date_utils.py
+++ b/odoo/tools/date_utils.py
@@ -2,8 +2,10 @@
 
 import math
 import calendar
+from datetime import date, datetime, time
 
 from dateutil.relativedelta import relativedelta
+from . import ustr
 
 
 def get_month(date):
@@ -62,3 +64,117 @@ def get_fiscal_year(date, day=31, month=12):
         max_day = calendar.monthrange(date_to.year + 1, date_to.month)[1]
         date_to = type(date)(date.year + 1, month, min(day, max_day))
     return date_from, date_to
+
+
+def start_of(value, granularity):
+    """
+    Get start of a time period from a date or a datetime.
+
+    :param value: initial date or datetime.
+    :param granularity: type of period in string, can be year, quarter, month, week, day or hour.
+    :return: a date/datetime object corresponding to the start of the specified period.
+    """
+    is_datetime = isinstance(value, datetime)
+    if granularity == "year":
+        result = value.replace(month=1, day=1)
+    elif granularity == "quarter":
+        # Q1 = Jan 1st
+        # Q2 = Apr 1st
+        # Q3 = Jul 1st
+        # Q4 = Oct 1st
+        result = get_quarter(value)[0]
+    elif granularity == "month":
+        result = value.replace(day=1)
+    elif granularity == 'week':
+        # `calendar.weekday` uses ISO8601 for start of week reference, this means that
+        # by default MONDAY is the first day of the week and SUNDAY is the last.
+        result = value - relativedelta(days=calendar.weekday(value.year, value.month, value.day))
+    elif granularity == "day":
+        result = value
+    elif granularity == "hour" and is_datetime:
+        return datetime.combine(value, time.min).replace(hour=value.hour)
+    elif is_datetime:
+        raise ValueError(
+            "Granularity must be year, quarter, month, week, day or hour for value %s" % value
+        )
+    else:
+        raise ValueError(
+            "Granularity must be year, quarter, month, week or day for value %s" % value
+        )
+
+    return datetime.combine(result, time.min) if is_datetime else result
+
+
+def end_of(value, granularity):
+    """
+    Get end of a time period from a date or a datetime.
+
+    :param value: initial date or datetime.
+    :param granularity: Type of period in string, can be year, quarter, month, week, day or hour.
+    :return: A date/datetime object corresponding to the start of the specified period.
+    """
+    is_datetime = isinstance(value, datetime)
+    if granularity == "year":
+        result = value.replace(month=12, day=31)
+    elif granularity == "quarter":
+        # Q1 = Mar 31st
+        # Q2 = Jun 30th
+        # Q3 = Sep 30th
+        # Q4 = Dec 31st
+        result = get_quarter(value)[1]
+    elif granularity == "month":
+        result = value + relativedelta(day=1, months=1, days=-1)
+    elif granularity == 'week':
+        # `calendar.weekday` uses ISO8601 for start of week reference, this means that
+        # by default MONDAY is the first day of the week and SUNDAY is the last.
+        result = value + relativedelta(days=6-calendar.weekday(value.year, value.month, value.day))
+    elif granularity == "day":
+        result = value
+    elif granularity == "hour" and is_datetime:
+        return datetime.combine(value, time.max).replace(hour=value.hour)
+    elif is_datetime:
+        raise ValueError(
+            "Granularity must be year, quarter, month, week, day or hour for value %s" % value
+        )
+    else:
+        raise ValueError(
+            "Granularity must be year, quarter, month, week or day for value %s" % value
+        )
+
+    return datetime.combine(result, time.max) if is_datetime else result
+
+
+def add(value, *args, **kwargs):
+    """
+    Return the sum of ``value`` and a :class:`relativedelta`.
+
+    :param value: initial date or datetime.
+    :param args: positional args to pass directly to :class:`relativedelta`.
+    :param kwargs: keyword args to pass directly to :class:`relativedelta`.
+    :return: the resulting date/datetime.
+    """
+    return value + relativedelta(*args, **kwargs)
+
+
+def subtract(value, *args, **kwargs):
+    """
+    Return the difference between ``value`` and a :class:`relativedelta`.
+
+    :param value: initial date or datetime.
+    :param args: positional args to pass directly to :class:`relativedelta`.
+    :param kwargs: keyword args to pass directly to :class:`relativedelta`.
+    :return: the resulting date/datetime.
+    """
+    return value - relativedelta(*args, **kwargs)
+
+
+def json_default(obj):
+    """
+    Properly serializes date and datetime objects.
+    """
+    from odoo import fields
+    if isinstance(obj, date):
+        if isinstance(obj, datetime):
+            return fields.Datetime.to_string(obj)
+        return fields.Date.to_string(obj)
+    return ustr(obj)