diff --git a/indigo_api/migrations/0021_document_expression_date.py b/indigo_api/migrations/0021_document_expression_date.py
index aee9c1229..c7c26041f 100644
--- a/indigo_api/migrations/0021_document_expression_date.py
+++ b/indigo_api/migrations/0021_document_expression_date.py
@@ -1,12 +1,12 @@
 # -*- coding: utf-8 -*-
-import arrow
 from django.db import models, migrations
 from indigo_api.models import Document
+from django.utils.timezone import now
 
 
 def forwards(apps, schema_editor):
     for doc in Document.objects.select_related(None).only('document_xml', 'expression_date').all():
-        doc.expression_date = doc.publication_date or arrow.now().date()
+        doc.expression_date = doc.publication_date or now().date()
         doc.save()
 
 
diff --git a/indigo_api/migrations/0042_add_repeal_works.py b/indigo_api/migrations/0042_add_repeal_works.py
index 0f7f1fc0b..0bf27554d 100644
--- a/indigo_api/migrations/0042_add_repeal_works.py
+++ b/indigo_api/migrations/0042_add_repeal_works.py
@@ -3,7 +3,7 @@
 from django.db import migrations
 
 from cobalt.act import datestring
-import arrow
+from iso8601 import parse_date
 
 
 def create_repeals(apps, schema_editor):
@@ -18,7 +18,7 @@ def create_repeals(apps, schema_editor):
 
     for doc in documents:
         if doc.repeal_event:
-            date = arrow.get(doc.repeal_event['date']).date()
+            date = parse_date(doc.repeal_event['date']).date()
 
             work = works.get(doc.repeal_event['repealing_uri'])
             if not work:
diff --git a/indigo_api/migrations/0046_works_for_amendments.py b/indigo_api/migrations/0046_works_for_amendments.py
index 17c5ceb48..4d0616655 100644
--- a/indigo_api/migrations/0046_works_for_amendments.py
+++ b/indigo_api/migrations/0046_works_for_amendments.py
@@ -1,7 +1,7 @@
 # -*- coding: utf-8 -*-
 # Generated by Django 1.11.8 on 2018-04-16 14:56
 from django.db import migrations
-import arrow
+from iso8601 import parse_date
 
 from cobalt.act import FrbrUri
 
@@ -19,7 +19,7 @@ def create_amendments(apps, schema_editor):
     for doc in documents:
         for amendment in (doc.amendment_events or []):
             work = works.get(amendment['amending_uri'])
-            date = arrow.get(amendment['date']).date()
+            date = parse_date(amendment['date']).date()
 
             if not work:
                 # validate frbr_uri
diff --git a/indigo_api/models/documents.py b/indigo_api/models/documents.py
index 6b441b219..87a6b94db 100644
--- a/indigo_api/models/documents.py
+++ b/indigo_api/models/documents.py
@@ -16,7 +16,7 @@
 from django.urls import reverse
 from django.utils import timezone
 from allauth.account.utils import user_display
-import arrow
+from iso8601 import parse_date, ParseError
 from taggit.managers import TaggableManager
 import reversion.revisions
 import reversion.models
@@ -79,18 +79,18 @@ def get_for_frbr_uri(self, frbr_uri):
 
             elif expr_date[0] == '@':
                 # document at this date
-                query = query.filter(expression_date=arrow.get(expr_date[1:]).date())
+                query = query.filter(expression_date=parse_date(expr_date[1:]).date())
 
             elif expr_date[0] == ':':
                 # latest document at or before this date
                 query = query \
-                    .filter(expression_date__lte=arrow.get(expr_date[1:]).date()) \
+                    .filter(expression_date__lte=parse_date(expr_date[1:]).date()) \
                     .order_by('-expression_date')
 
             else:
                 raise ValueError("The expression date %s is not valid" % expr_date)
 
-        except arrow.parser.ParserError:
+        except ParseError:
             raise ValueError("The expression date %s is not valid" % expr_date)
 
         obj = query.first()
@@ -330,8 +330,8 @@ def copy_attributes(self, from_model=True):
             self.doc.language = self.language.code
 
             self.doc.work_date = self.doc.publication_date
-            self.doc.expression_date = self.expression_date or self.doc.publication_date or arrow.now()
-            self.doc.manifestation_date = self.updated_at or arrow.now()
+            self.doc.expression_date = self.expression_date or self.doc.publication_date or timezone.now()
+            self.doc.manifestation_date = self.updated_at or timezone.now()
             self.doc.publication_number = self.publication_number
             self.doc.publication_name = self.publication_name
             self.doc.publication_date = self.publication_date
diff --git a/setup.py b/setup.py
index a337dda82..f0990f3f9 100644
--- a/setup.py
+++ b/setup.py
@@ -41,9 +41,8 @@
     python_requires='~=3.6',
     install_requires=[
         'django>=1.11.27,<2',
-        'arrow>=0.5',
         'boto3>=1.7',
-        'cobalt>=3.0',
+        'cobalt>=3.1',
         'django-ckeditor>=5.8',
         'dj-database-url>=0.3.0',
         'django-activity-stream>=0.7.0',
@@ -70,6 +69,7 @@
         'djangorestframework>=3.6.2,<3.7',
         'EbookLib>=0.15',
         'google-api-python-client>=1.7.9',
+        'iso8601>=0.1',
         'jsonpatch>=1.23',
         'libsass==0.14.2',  # 0.14.3 upwards changes imports for .css
         'lxml>=3.4.1',