diff --git a/.codeclimate.yml b/.codeclimate.yml
index fb8b35669b..84be589cd9 100644
--- a/.codeclimate.yml
+++ b/.codeclimate.yml
@@ -35,7 +35,6 @@ exclude_patterns:
   - "app/javascript"
   - "assets/bundles/*.js"
   - "bin/webpack*"
-  - "lib/action_dispatch/rails5_ssl.rb"
   - "lib/developer_portal/app/assets/stylesheets/**/*"
   - "lib/developer_portal/app/views/developer_portal/css/*"
   - "lib/developer_portal/app/views/developer_portal/javascripts/*"
diff --git a/Gemfile b/Gemfile
index e2280d58fd..e635a7f586 100644
--- a/Gemfile
+++ b/Gemfile
@@ -12,8 +12,7 @@ gem 'aws-sdk-rails', '~> 3'
 gem 'aws-sdk-s3', '~> 1'
 
 gem 'dotenv-rails', '~> 2.7'
-gem 'rails', '~> 5.2.8'
-gem 'globalid', '~> 1.0.1' # remove line after we stop supporting Ruby 2.4
+gem 'rails', '~> 6.0'
 
 # Locking mail to 2.7.x, as 2.8 has a regression related to `enable_starttls_auto` setting:
 # https://github.com/mikel/mail/blob/2-8-stable/CHANGELOG.rdoc#version-281-unreleased-
@@ -33,10 +32,10 @@ gem 'strong_migrations', '~> 0.6.8'
 group :assets do
   gem 'coffee-rails', '~> 5.0'
   gem 'non-stupid-digest-assets', '~> 1.0'
-  gem 'sprockets-rails', '3.2.2' # remove version after we stop supporting Ruby 2.4
+  gem 'sprockets-rails'
 end
 
-gem 'sass-rails', '~> 5.0'
+gem 'sass-rails', '~> 5.0.8'
 
 gem 'bcrypt', '~> 3.1.7'
 gem 'oauth2', '~> 1.4'
@@ -77,7 +76,6 @@ gem 'formtastic', '~> 4.0'
 gem 'htmlentities', '~>4.3', '>= 4.3.4'
 # TODO: Not actively maintained https://github.com/activeadmin/inherited_resources#notice replace with respond_with and fix things the rails way
 gem 'inherited_resources', '~> 1.12.0'
-gem 'has_scope', '~> 0.7.2' # remove line after we stop supporting Ruby 2.4
 gem 'json', '~> 2.3.0'
 
 gem 'mysql2', '~> 0.5.3'
@@ -85,7 +83,7 @@ gem 'mysql2', '~> 0.5.3'
 gem '3scale_client', '~> 2.11', require: false
 gem 'analytics-ruby', require: false
 
-gem 'dalli', '~> 2.7' # remove version once we stop supporting ruby 2.4
+gem 'dalli'
 gem 'faraday', '~> 0.15.3'
 gem 'faraday_middleware', '~> 0.13.1'
 gem 'mimemagic', '~> 0.3.10'
@@ -95,8 +93,7 @@ gem 'redlock'
 
 gem 'acts-as-taggable-on', '~> 8.0'
 gem 'baby_squeel', '~> 1.4.3'
-gem 'ransack', '2.4.1' # we can remove line when stop using ruby 2.4
-gem 'browser', '~> 5.0.0' # we can update to lts when we stop using ruby 2.4
+gem 'browser'
 gem 'diff-lcs', '~> 1.2'
 gem 'hiredis', '~> 0.6.3'
 gem 'httpclient', github: '3scale/httpclient', branch: 'ssl-env-cert'
@@ -149,7 +146,7 @@ gem 'compass-rails', '~> 3.0.2'
 
 gem 'after_commit_queue', '~> 1.1.0'
 gem 'state_machines', '~> 0.5.0'
-gem 'state_machines-activerecord', '~> 0.5.0'
+gem 'state_machines-activerecord', '~> 0.8'
 
 # for liquid docs on-fly generation
 gem 'commonmarker', '~> 0.23.9'
@@ -161,7 +158,7 @@ gem 'html-pipeline'
 gem 'ruby-openid'
 gem 'slim-rails', '~> 3.2'
 
-gem 'draper', '~> 3.0'
+gem 'draper', '~> 3.1'
 
 group :development do
   gem 'listen'
@@ -188,7 +185,7 @@ group :test do
   # To remove once migrated all functional tests
   gem 'codecov', :require => false
   gem 'rack-no_animations', '~> 1.0.3'
-  gem 'rails-controller-testing'
+  gem 'rails-controller-testing', '~> 1.0.4'
   gem 'simplecov', '~> 0.21.2', require: false
 
   gem 'capybara', '~>3.35.3', source: 'https://rubygems.org'
@@ -198,7 +195,7 @@ group :test do
   gem 'cucumber', '~> 7.0'
   gem 'cucumber-rails', '~> 2.4.0', require: false
   gem 'email_spec', require: false
-  gem 'fakefs', '~>0.18.0', require: 'fakefs/safe'
+  gem 'fakefs', require: 'fakefs/safe'
   gem 'launchy'
   gem 'mechanize'
   gem 'selenium-webdriver', '~> 3.142', require: false
@@ -239,7 +236,7 @@ group :test do
 end
 
 group :development, :test do
-  gem 'bootsnap', '~> 1.4'
+  gem 'bootsnap', '~> 1.16'
   gem 'bullet', '~> 6.1.5'
   gem 'colorize'
   gem 'factory_bot_rails', '~> 6.2'
@@ -265,11 +262,10 @@ gem 'unicorn', require: false, group: %i[production]
 # NOTE: Use ENV['DB'] only to install oracle dependencies
 group :oracle do
   oracle = -> { (ENV['ORACLE'] == '1') || ENV.fetch('DATABASE_URL', ENV['DB'])&.start_with?('oracle') }
-  gem 'activerecord-oracle_enhanced-adapter', '~> 5.2.0', install_if: oracle
+  gem 'activerecord-oracle_enhanced-adapter', '~> 6.0', install_if: oracle
   gem 'ruby-oci8', require: false, install_if: oracle
 end
 
 gem 'kubeclient'
-gem 'jsonpath', '1.0.5' # remove line after we stop supporting ruby 2.4
 
 gem 'pg', '~> 0.21.0'
diff --git a/Gemfile.lock b/Gemfile.lock
index 6ab5cae3db..c689cf9292 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -81,59 +81,73 @@ GEM
       activesupport (>= 3.2.19)
     Ascii85 (1.1.0)
     RedCloth (4.3.2)
-    actioncable (5.2.8.1)
-      actionpack (= 5.2.8.1)
+    actioncable (6.0.6.1)
+      actionpack (= 6.0.6.1)
       nio4r (~> 2.0)
       websocket-driver (>= 0.6.1)
-    actionmailer (5.2.8.1)
-      actionpack (= 5.2.8.1)
-      actionview (= 5.2.8.1)
-      activejob (= 5.2.8.1)
+    actionmailbox (6.0.6.1)
+      actionpack (= 6.0.6.1)
+      activejob (= 6.0.6.1)
+      activerecord (= 6.0.6.1)
+      activestorage (= 6.0.6.1)
+      activesupport (= 6.0.6.1)
+      mail (>= 2.7.1)
+    actionmailer (6.0.6.1)
+      actionpack (= 6.0.6.1)
+      actionview (= 6.0.6.1)
+      activejob (= 6.0.6.1)
       mail (~> 2.5, >= 2.5.4)
       rails-dom-testing (~> 2.0)
-    actionpack (5.2.8.1)
-      actionview (= 5.2.8.1)
-      activesupport (= 5.2.8.1)
+    actionpack (6.0.6.1)
+      actionview (= 6.0.6.1)
+      activesupport (= 6.0.6.1)
       rack (~> 2.0, >= 2.0.8)
       rack-test (>= 0.6.3)
       rails-dom-testing (~> 2.0)
-      rails-html-sanitizer (~> 1.0, >= 1.0.2)
-    actionview (5.2.8.1)
-      activesupport (= 5.2.8.1)
+      rails-html-sanitizer (~> 1.0, >= 1.2.0)
+    actiontext (6.0.6.1)
+      actionpack (= 6.0.6.1)
+      activerecord (= 6.0.6.1)
+      activestorage (= 6.0.6.1)
+      activesupport (= 6.0.6.1)
+      nokogiri (>= 1.8.5)
+    actionview (6.0.6.1)
+      activesupport (= 6.0.6.1)
       builder (~> 3.1)
       erubi (~> 1.4)
       rails-dom-testing (~> 2.0)
-      rails-html-sanitizer (~> 1.0, >= 1.0.3)
-    activejob (5.2.8.1)
-      activesupport (= 5.2.8.1)
+      rails-html-sanitizer (~> 1.1, >= 1.2.0)
+    activejob (6.0.6.1)
+      activesupport (= 6.0.6.1)
       globalid (>= 0.3.6)
     activemerchant (1.107.4)
       activesupport (>= 4.2)
       builder (>= 2.1.2, < 4.0.0)
       i18n (>= 0.6.9)
       nokogiri (~> 1.4)
-    activemodel (5.2.8.1)
-      activesupport (= 5.2.8.1)
+    activemodel (6.0.6.1)
+      activesupport (= 6.0.6.1)
     activemodel-serializers-xml (1.0.2)
       activemodel (> 5.x)
       activesupport (> 5.x)
       builder (~> 3.1)
-    activerecord (5.2.8.1)
-      activemodel (= 5.2.8.1)
-      activesupport (= 5.2.8.1)
-      arel (>= 9.0)
-    activerecord-oracle_enhanced-adapter (5.2.8)
-      activerecord (~> 5.2.0)
+    activerecord (6.0.6.1)
+      activemodel (= 6.0.6.1)
+      activesupport (= 6.0.6.1)
+    activerecord-oracle_enhanced-adapter (6.0.6)
+      activerecord (~> 6.0.0)
       ruby-plsql (>= 0.6.0)
-    activestorage (5.2.8.1)
-      actionpack (= 5.2.8.1)
-      activerecord (= 5.2.8.1)
-      marcel (~> 1.0.0)
-    activesupport (5.2.8.1)
+    activestorage (6.0.6.1)
+      actionpack (= 6.0.6.1)
+      activejob (= 6.0.6.1)
+      activerecord (= 6.0.6.1)
+      marcel (~> 1.0)
+    activesupport (6.0.6.1)
       concurrent-ruby (~> 1.0, >= 1.0.2)
       i18n (>= 0.7, < 2)
       minitest (~> 5.1)
       tzinfo (~> 1.1)
+      zeitwerk (~> 2.2, >= 2.2.2)
     acts-as-taggable-on (8.1.0)
       activerecord (>= 5.0, < 6.2)
     acts_as_list (0.9.17)
@@ -149,7 +163,6 @@ GEM
       activesupport (>= 3.0)
     analytics-ruby (2.2.8)
     ansi (1.5.0)
-    arel (9.0.0)
     ast (2.4.2)
     audited (5.0.2)
       activerecord (>= 5.0, < 7.1)
@@ -196,11 +209,11 @@ GEM
     bcrypt (3.1.13)
     binding_of_caller (1.0.0)
       debug_inspector (>= 0.0.1)
-    bootsnap (1.4.5)
-      msgpack (~> 1.0)
+    bootsnap (1.16.0)
+      msgpack (~> 1.2)
     braintree (2.104.1)
       builder (>= 2.0.0)
-    browser (5.0.0)
+    browser (5.3.1)
     bugsnag (6.11.1)
       concurrent-ruby (~> 1.0)
     builder (3.2.4)
@@ -298,7 +311,7 @@ GEM
       cucumber-cucumber-expressions (~> 12.1, >= 12.1.2)
       cucumber-messages (~> 17.0, >= 17.0.1)
     daemons (1.3.1)
-    dalli (2.7.10)
+    dalli (3.2.4)
     database_cleaner (1.7.0)
     debug_inspector (1.1.0)
     diff-lcs (1.4.4)
@@ -313,12 +326,12 @@ GEM
     dotenv-rails (2.7.5)
       dotenv (= 2.7.5)
       railties (>= 3.2, < 6.1)
-    draper (3.0.1)
-      actionpack (~> 5.0)
-      activemodel (~> 5.0)
-      activemodel-serializers-xml (~> 1.0)
-      activesupport (~> 5.0)
-      request_store (~> 1.0)
+    draper (3.1.0)
+      actionpack (>= 5.0)
+      activemodel (>= 5.0)
+      activemodel-serializers-xml (>= 1.0)
+      activesupport (>= 5.0)
+      request_store (>= 1.0)
     dry-initializer (3.0.4)
     dynamic_form (1.1.4)
     email_spec (2.2.0)
@@ -338,7 +351,7 @@ GEM
     factory_bot_rails (6.2.0)
       factory_bot (~> 6.2.0)
       railties (>= 5.0.0)
-    fakefs (0.18.0)
+    fakefs (1.8.0)
     faraday (0.15.3)
       multipart-post (>= 1.2, < 3)
     faraday_middleware (0.13.1)
@@ -355,11 +368,11 @@ GEM
       et-orbi (~> 1.1, >= 1.1.8)
       raabro (~> 1.4)
     github-markdown (0.6.9)
-    globalid (1.0.1)
+    globalid (1.1.0)
       activesupport (>= 5.0)
-    has_scope (0.7.2)
-      actionpack (>= 4.1)
-      activesupport (>= 4.1)
+    has_scope (0.8.1)
+      actionpack (>= 5.2)
+      activesupport (>= 5.2)
     hashdiff (1.0.1)
     hashery (2.1.2)
     hashie (3.6.0)
@@ -395,9 +408,8 @@ GEM
       railties (>= 4.2.0)
       thor (>= 0.14, < 2.0)
     json (2.3.1)
-    jsonpath (1.0.5)
+    jsonpath (1.1.2)
       multi_json
-      to_regexp (~> 0.2.1)
     jwt (1.5.6)
     kgio (2.11.3)
     kramdown (2.4.0)
@@ -466,7 +478,7 @@ GEM
     minitest-stub-const (0.6)
     mocha (1.1.0)
       metaclass (~> 0.0.1)
-    msgpack (1.3.1)
+    msgpack (1.7.1)
     multi_json (1.15.0)
     multi_test (0.1.2)
     multi_xml (0.6.0)
@@ -478,7 +490,7 @@ GEM
     net-http-persistent (4.0.1)
       connection_pool (~> 2.2)
     netrc (0.11.0)
-    nio4r (2.5.8)
+    nio4r (2.5.9)
     nokogiri (1.13.10)
       mini_portile2 (~> 2.8.0)
       racc (~> 1.4)
@@ -550,7 +562,7 @@ GEM
     public_suffix (4.0.7)
     raabro (1.4.0)
     racc (1.6.2)
-    rack (2.2.6.4)
+    rack (2.2.7)
     rack-cors (1.1.1)
       rack (>= 2.0.0)
     rack-no_animations (1.0.3)
@@ -566,23 +578,25 @@ GEM
     rack-utf8_sanitizer (1.6.0)
       rack (>= 1.0, < 3.0)
     rack-x_served_by (0.1.1)
-    rails (5.2.8.1)
-      actioncable (= 5.2.8.1)
-      actionmailer (= 5.2.8.1)
-      actionpack (= 5.2.8.1)
-      actionview (= 5.2.8.1)
-      activejob (= 5.2.8.1)
-      activemodel (= 5.2.8.1)
-      activerecord (= 5.2.8.1)
-      activestorage (= 5.2.8.1)
-      activesupport (= 5.2.8.1)
+    rails (6.0.6.1)
+      actioncable (= 6.0.6.1)
+      actionmailbox (= 6.0.6.1)
+      actionmailer (= 6.0.6.1)
+      actionpack (= 6.0.6.1)
+      actiontext (= 6.0.6.1)
+      actionview (= 6.0.6.1)
+      activejob (= 6.0.6.1)
+      activemodel (= 6.0.6.1)
+      activerecord (= 6.0.6.1)
+      activestorage (= 6.0.6.1)
+      activesupport (= 6.0.6.1)
       bundler (>= 1.3.0)
-      railties (= 5.2.8.1)
+      railties (= 6.0.6.1)
       sprockets-rails (>= 2.0.0)
-    rails-controller-testing (1.0.2)
-      actionpack (~> 5.x, >= 5.0.1)
-      actionview (~> 5.x, >= 5.0.1)
-      activesupport (~> 5.x)
+    rails-controller-testing (1.0.5)
+      actionpack (>= 5.0.1.rc1)
+      actionview (>= 5.0.1.rc1)
+      activesupport (>= 5.0.1.rc1)
     rails-dom-testing (2.0.3)
       activesupport (>= 4.2.0)
       nokogiri (>= 1.6)
@@ -600,18 +614,18 @@ GEM
       activemodel (>= 3.0)
       activesupport (>= 3.0)
       ruby_event_store (~> 0.9.0)
-    railties (5.2.8.1)
-      actionpack (= 5.2.8.1)
-      activesupport (= 5.2.8.1)
+    railties (6.0.6.1)
+      actionpack (= 6.0.6.1)
+      activesupport (= 6.0.6.1)
       method_source
       rake (>= 0.8.7)
-      thor (>= 0.19.0, < 2.0)
+      thor (>= 0.20.3, < 2.0)
     rainbow (3.1.1)
     raindrops (0.19.0)
     rake (13.0.6)
-    ransack (2.4.1)
-      activerecord (>= 5.2.4)
-      activesupport (>= 5.2.4)
+    ransack (2.6.0)
+      activerecord (>= 6.0.4)
+      activesupport (>= 6.0.4)
       i18n
     ratelimit (1.0.3)
       redis (>= 2.0.0)
@@ -629,8 +643,8 @@ GEM
     redis-namespace (1.7.0)
       redis (>= 3.0.4)
     redis-prescription (1.0.0)
-    redlock (1.2.1)
-      redis (>= 3.0.0, < 5.0)
+    redlock (1.3.2)
+      redis (>= 3.0.0, < 6.0)
     reek (6.1.0)
       kwalify (~> 0.7.0)
       parser (~> 3.1.0)
@@ -641,7 +655,7 @@ GEM
     regexp_parser (2.6.1)
     representable (2.3.0)
       uber (~> 0.0.7)
-    request_store (1.4.1)
+    request_store (1.5.1)
       rack (>= 1.4)
     responders (3.0.1)
       actionpack (>= 5.0)
@@ -717,8 +731,8 @@ GEM
     ruby_event_store (0.9.0)
     rubyzip (1.3.0)
     sass (3.4.25)
-    sass-rails (5.0.7)
-      railties (>= 4.0.0, < 6)
+    sass-rails (5.0.8)
+      railties (>= 5.2.0)
       sass (~> 3.1)
       sprockets (>= 2.8, < 4.0)
       sprockets-rails (>= 2.0, < 4.0)
@@ -769,17 +783,17 @@ GEM
     sprockets (3.7.2)
       concurrent-ruby (~> 1.0)
       rack (> 1, < 3)
-    sprockets-rails (3.2.2)
-      actionpack (>= 4.0)
-      activesupport (>= 4.0)
+    sprockets-rails (3.4.2)
+      actionpack (>= 5.2)
+      activesupport (>= 5.2)
       sprockets (>= 3.0.0)
     state_machines (0.5.0)
-    state_machines-activemodel (0.5.1)
-      activemodel (>= 4.1, < 6.0)
+    state_machines-activemodel (0.8.0)
+      activemodel (>= 5.1)
       state_machines (>= 0.5.0)
-    state_machines-activerecord (0.5.2)
-      activerecord (>= 4.1, < 6.0)
-      state_machines-activemodel (>= 0.5.0)
+    state_machines-activerecord (0.8.0)
+      activerecord (>= 5.1)
+      state_machines-activemodel (>= 0.8.0)
     statsd-ruby (1.4.0)
     strings (0.2.1)
       strings-ansi (~> 0.2)
@@ -811,8 +825,7 @@ GEM
       riddle (~> 2.3)
     thor (1.2.2)
     thread_safe (0.3.6)
-    tilt (2.0.9)
-    to_regexp (0.2.1)
+    tilt (2.0.11)
     tomlrb (2.0.3)
     ts-datetime-delta (2.0.2)
       thinking-sphinx (>= 1.3.8)
@@ -886,6 +899,7 @@ GEM
       yabeda (~> 0.6)
     yard (0.9.27)
       webrick (~> 1.7.0)
+    zeitwerk (2.6.8)
     zip-zip (0.3)
       rubyzip (>= 1.0.0)
 
@@ -900,7 +914,7 @@ DEPENDENCIES
   activejob-uniqueness!
   activemerchant (~> 1.107.4)
   activemodel-serializers-xml
-  activerecord-oracle_enhanced-adapter (~> 5.2.0)
+  activerecord-oracle_enhanced-adapter (~> 6.0)
   acts-as-taggable-on (~> 8.0)
   acts_as_list (~> 0.9.17)
   acts_as_tree
@@ -912,9 +926,9 @@ DEPENDENCIES
   aws-sdk-s3 (~> 1)
   baby_squeel (~> 1.4.3)
   bcrypt (~> 3.1.7)
-  bootsnap (~> 1.4)
+  bootsnap (~> 1.16)
   braintree (~> 2.93)
-  browser (~> 5.0.0)
+  browser
   bugsnag (~> 6.11)
   bullet (~> 6.1.5)
   cancancan (~> 3.0.0)
@@ -929,25 +943,23 @@ DEPENDENCIES
   compass-rails (~> 3.0.2)
   cucumber (~> 7.0)
   cucumber-rails (~> 2.4.0)
-  dalli (~> 2.7)
+  dalli
   database_cleaner (~> 1.7)
   developer_portal!
   diff-lcs (~> 1.2)
   dotenv-rails (~> 2.7)
-  draper (~> 3.0)
+  draper (~> 3.1)
   dynamic_form
   email_spec
   equivalent-xml
   escape_utils
   factory_bot_rails (~> 6.2)
-  fakefs (~> 0.18.0)
+  fakefs
   faraday (~> 0.15.3)
   faraday_middleware (~> 0.13.1)
   font-awesome-rails (~> 4.7.0.5)
   formtastic (~> 4.0)
   github-markdown
-  globalid (~> 1.0.1)
-  has_scope (~> 0.7.2)
   hashie
   hiredis (~> 0.6.3)
   html-pipeline
@@ -958,7 +970,6 @@ DEPENDENCIES
   jquery-rails (~> 4.4)
   json (~> 2.3.0)
   json-schema!
-  jsonpath (= 1.0.5)
   jwt (~> 1.5.2)
   kubeclient
   launchy
@@ -999,11 +1010,10 @@ DEPENDENCIES
   rack-no_animations (~> 1.0.3)
   rack-utf8_sanitizer
   rack-x_served_by (~> 0.1.1)
-  rails (~> 5.2.8)
-  rails-controller-testing
+  rails (~> 6.0)
+  rails-controller-testing (~> 1.0.4)
   rails-observers
   rails_event_store (~> 0.9.0)
-  ransack (= 2.4.1)
   ratelimit
   recaptcha (= 4.13.1)
   record_tag_helper (~> 1.0)
@@ -1026,7 +1036,7 @@ DEPENDENCIES
   ruby-openid
   ruby-prof
   rubyzip (~> 1.3.0)
-  sass-rails (~> 5.0)
+  sass-rails (~> 5.0.8)
   secure_headers (~> 6.3.0)
   selenium-webdriver (~> 3.142)
   shoulda (~> 4.0)
@@ -1038,9 +1048,9 @@ DEPENDENCIES
   sidekiq-throttled
   simplecov (~> 0.21.2)
   slim-rails (~> 3.2)
-  sprockets-rails (= 3.2.2)
+  sprockets-rails
   state_machines (~> 0.5.0)
-  state_machines-activerecord (~> 0.5.0)
+  state_machines-activerecord (~> 0.8)
   statsd-ruby
   stripe (~> 5.28.0)
   strong_migrations (~> 0.6.8)
diff --git a/app/controllers/admin/api/sso_tokens_controller.rb b/app/controllers/admin/api/sso_tokens_controller.rb
index 87cff3ddd5..f71ba7277e 100644
--- a/app/controllers/admin/api/sso_tokens_controller.rb
+++ b/app/controllers/admin/api/sso_tokens_controller.rb
@@ -19,7 +19,7 @@ def provider_create
     provider = site_account.buyers.find(params[:provider_id])
     sso_token = SSOToken.new
     sso_token.account = provider
-    sso_token.username = ThreeScale.config.impersonation_admin['username']
+    sso_token.username = ThreeScale.config.impersonation_admin[:username]
     sso_token.expires_in = params.fetch(:expires_in) { sso_token.expires_in }
 
     sso_token.save
diff --git a/app/controllers/provider/admin/dashboard/service/hits_controller.rb b/app/controllers/provider/admin/dashboard/service/hits_controller.rb
index 818cfc1d84..01e07c07be 100644
--- a/app/controllers/provider/admin/dashboard/service/hits_controller.rb
+++ b/app/controllers/provider/admin/dashboard/service/hits_controller.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class Provider::Admin::Dashboard::Service::HitsController < Provider::Admin::Dashboard::Service::BaseController
   include ActiveSupport::NumberHelper
 
@@ -31,4 +33,3 @@ def traffic_service
     TrafficService.new(stats_client)
   end
 end
-require_dependency 'stats/service'
diff --git a/app/controllers/provider/admin/dashboard/service/top_traffic_controller.rb b/app/controllers/provider/admin/dashboard/service/top_traffic_controller.rb
index 2aefbec0c5..39fe69063e 100644
--- a/app/controllers/provider/admin/dashboard/service/top_traffic_controller.rb
+++ b/app/controllers/provider/admin/dashboard/service/top_traffic_controller.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class Provider::Admin::Dashboard::Service::TopTrafficController < Provider::Admin::Dashboard::Service::BaseController
   respond_to :json
 
@@ -13,4 +15,3 @@ def stats_client
     ::Stats::Service.new(service)
   end
 end
-require_dependency 'stats/service'
diff --git a/app/lib/authentication/strategy.rb b/app/lib/authentication/strategy.rb
index b75866f43d..171103bec7 100644
--- a/app/lib/authentication/strategy.rb
+++ b/app/lib/authentication/strategy.rb
@@ -15,7 +15,8 @@ def build_provider(provider_account)
       protected
 
       def build_strategy(type)
-        strategy_class_name = "authentication/strategy/#{type}".camelize
+        inflected_type = Rails.autoloaders.main.inflector.camelize(type.to_s, {})
+        strategy_class_name = "Authentication::Strategy::#{inflected_type}"
         strategy_class_name.constantize
       end
     end
diff --git a/app/lib/authentication/strategy/base.rb b/app/lib/authentication/strategy/base.rb
index 406162af2e..ff4254e366 100644
--- a/app/lib/authentication/strategy/base.rb
+++ b/app/lib/authentication/strategy/base.rb
@@ -80,7 +80,7 @@ def authentication_provider; end
 
       def authentication_provider_id
         authentication_provider.try(:id)
-      rescue Authentication::Strategy::Oauth2Base::MissingAuthenticationProvider
+      rescue Authentication::Strategy::OAuth2Base::MissingAuthenticationProvider
         nil
       end
     end
diff --git a/app/lib/authentication/strategy/oauth2.rb b/app/lib/authentication/strategy/oauth2.rb
index 97a2663db5..17e0aade93 100644
--- a/app/lib/authentication/strategy/oauth2.rb
+++ b/app/lib/authentication/strategy/oauth2.rb
@@ -2,7 +2,7 @@
 
 module Authentication
   module Strategy
-    class Oauth2 < Authentication::Strategy::Oauth2Base
+    class OAuth2 < Authentication::Strategy::OAuth2Base
       class FindOrCreateAccount < Procedure
 
         def call
@@ -12,7 +12,7 @@ def call
         private
 
         def find_user
-          Users::FindOauth2UserService.run(user_data, authentication_provider, users).user.tap do |user|
+          Users::FindOAuth2UserService.run(user_data, authentication_provider, users).user.tap do |user|
             strategy.user_used_sso_authorization(user, user_data) if user
           end
         end
diff --git a/app/lib/authentication/strategy/oauth2_base.rb b/app/lib/authentication/strategy/oauth2_base.rb
index 83f8a69045..34ed51b456 100644
--- a/app/lib/authentication/strategy/oauth2_base.rb
+++ b/app/lib/authentication/strategy/oauth2_base.rb
@@ -2,7 +2,7 @@
 
 module Authentication
   module Strategy
-    class Oauth2Base < Authentication::Strategy::Internal
+    class OAuth2Base < Authentication::Strategy::Internal
 
       def initialize(*)
         super
diff --git a/app/lib/authentication/strategy/provider_oauth2.rb b/app/lib/authentication/strategy/provider_oauth2.rb
index 869822feeb..299e140012 100644
--- a/app/lib/authentication/strategy/provider_oauth2.rb
+++ b/app/lib/authentication/strategy/provider_oauth2.rb
@@ -1,6 +1,6 @@
 module Authentication
   module Strategy
-    class ProviderOauth2 < Authentication::Strategy::Oauth2Base
+    class ProviderOAuth2 < Authentication::Strategy::OAuth2Base
 
       class FindOrCreateUser < Procedure
 
@@ -13,7 +13,7 @@ def call
         private
 
         def find_user
-          result = Users::FindOauth2UserService.run(user_data, authentication_provider, users)
+          result = Users::FindOAuth2UserService.run(user_data, authentication_provider, users)
           strategy.error_message = result.error_message
           result.user
         end
diff --git a/app/lib/authentication/strategy/sso.rb b/app/lib/authentication/strategy/sso.rb
index 16f3650c36..5a9ad5ecd7 100644
--- a/app/lib/authentication/strategy/sso.rb
+++ b/app/lib/authentication/strategy/sso.rb
@@ -73,7 +73,7 @@ def authenticate_with_sso(token, expires_at = nil)
         @error_message = 'User not found'
         nil
       # this happens when we fail to decrypt the message
-      rescue ActiveSupport::MessageVerifier::InvalidSignature => error
+      rescue ActiveSupport::MessageEncryptor::InvalidMessage, ActiveSupport::MessageVerifier::InvalidSignature => error
         @error_message = "Invalid SSO Token"
         nil
       # this happens when we fail to validate the decrypted message, right now only if the token expired
diff --git a/app/lib/cms/database_file_system.rb b/app/lib/cms/database_file_system.rb
index 61b9c1cdd7..8ecf2d701f 100644
--- a/app/lib/cms/database_file_system.rb
+++ b/app/lib/cms/database_file_system.rb
@@ -47,8 +47,8 @@ def initialize(*)
       @details = { formats: [:html], handlers: [:liquid] }
     end
 
-    def find_template(path)
-      super(path, [])
+    def find_template(path, locals = [])
+      super(path, locals)
     end
   end
 
diff --git a/app/lib/events/importer.rb b/app/lib/events/importer.rb
index 3f07dbf5ce..283a528f9e 100644
--- a/app/lib/events/importer.rb
+++ b/app/lib/events/importer.rb
@@ -1,9 +1,4 @@
-require_dependency 'events/event'
-
-require_dependency 'events/importers/base_importer'
-require_dependency 'events/importers/first_traffic_importer'
-require_dependency 'events/importers/first_daily_traffic_importer'
-require_dependency 'events/importers/alert_importer'
+# frozen_string_literal: true
 
 module Events
   module Importer
diff --git a/app/lib/events/importers/alert_importer.rb b/app/lib/events/importers/alert_importer.rb
index 5339a53ffb..2f647e7bdc 100644
--- a/app/lib/events/importers/alert_importer.rb
+++ b/app/lib/events/importers/alert_importer.rb
@@ -1,4 +1,4 @@
-require_dependency 'events/importers/base_importer'
+# frozen_string_literal: true
 
 module Events
   module Importers
@@ -103,4 +103,3 @@ def settings
     end
   end
 end
-
diff --git a/app/lib/events/importers/first_daily_traffic_importer.rb b/app/lib/events/importers/first_daily_traffic_importer.rb
index 40ac54d305..a8b8f8c5bf 100644
--- a/app/lib/events/importers/first_daily_traffic_importer.rb
+++ b/app/lib/events/importers/first_daily_traffic_importer.rb
@@ -1,7 +1,5 @@
 # frozen_string_literal: true
 
-require_dependency 'events/importers/base_importer'
-
 module Events
   module Importers
     class FirstDailyTrafficImporter < BaseImporter
diff --git a/app/lib/events/importers/first_traffic_importer.rb b/app/lib/events/importers/first_traffic_importer.rb
index 0a0c05d315..f9daf00482 100644
--- a/app/lib/events/importers/first_traffic_importer.rb
+++ b/app/lib/events/importers/first_traffic_importer.rb
@@ -1,7 +1,5 @@
 # frozen_string_literal: true
 
-require_dependency 'events/importers/base_importer'
-
 module Events
   module Importers
     class FirstTrafficImporter < BaseImporter
diff --git a/app/lib/finance/variable_cost.rb b/app/lib/finance/variable_cost.rb
index 937b2e17b9..a4e85f86c8 100644
--- a/app/lib/finance/variable_cost.rb
+++ b/app/lib/finance/variable_cost.rb
@@ -1,4 +1,4 @@
-require_dependency 'stats/client'
+# frozen_string_literal: true
 
 module Finance
   # Mixin for Cinstance to get the variable costs calculations.
diff --git a/app/lib/last_traffic.rb b/app/lib/last_traffic.rb
index 7114597231..09e69b5f48 100644
--- a/app/lib/last_traffic.rb
+++ b/app/lib/last_traffic.rb
@@ -1,7 +1,5 @@
 # frozen_string_literal: true
 
-require_dependency 'stats'
-
 class LastTraffic
   DEFAULT_METRIC = 'hits'
 
diff --git a/app/lib/liquid/template_support.rb b/app/lib/liquid/template_support.rb
index ab36b6c3ed..fc176ddf18 100644
--- a/app/lib/liquid/template_support.rb
+++ b/app/lib/liquid/template_support.rb
@@ -48,7 +48,21 @@ def add_liquid_view_paths(options = {})
         end
       end
 
-      view_renderer.extend(LayoutSupport)
+      ActionView::Renderer.class_eval do
+        # RAILS: this overrides a Rails method. Beware when upgrading.
+        # We overwrite ActionView methods to make Liquid work. Due to changes in ActionView, we cannot depend on
+        # overwriting instances of ActionView::Renderer anymore, as those can be reinitialized during a page render.
+        # Because of that, we need to overwrite this method in class level, which may cause odd behaviours without
+        # the respond_to?(:liquify) check.
+        # Maybe move this to an initializer in case we can't find a better solution?
+        def render_template_to_object(context, options)
+          if context.controller.class.respond_to?(:liquify)
+            LiquidTemplateRenderer.new(@lookup_context).render(context, options)
+          else
+            ActionView::TemplateRenderer.new(@lookup_context).render(context, options)
+          end
+        end
+      end
     end
 
     class LiquidTemplateRenderer < ::ActionView::TemplateRenderer
@@ -68,13 +82,6 @@ def determine_template(options)
       end
     end
 
-    module LayoutSupport
-      # RAILS: this overrides rails method, beware when upgrading
-      def render_template(context, options)
-        LiquidTemplateRenderer.new(@lookup_context).render(context, options)
-      end
-    end
-
     def assigns_for_liquify
       @_assigned_drops ||= {}
       @_template_assigns ||= {}
diff --git a/app/lib/plan_rule_loader.rb b/app/lib/plan_rule_loader.rb
index 7b7cc984f1..c18067ec6c 100644
--- a/app/lib/plan_rule_loader.rb
+++ b/app/lib/plan_rule_loader.rb
@@ -3,9 +3,9 @@
 module PlanRuleLoader
   DEFAULT_RULES = {
     enterprise: {
-      'rank' => 27,
-      'limits' => {'max_users' => nil, 'max_services' => nil},
-      'switches' => %w[
+      rank: 27,
+      limits: { max_users: nil, max_services: nil },
+      switches: %w[
         finance
         multiple_applications
         branding
@@ -19,7 +19,7 @@ module PlanRuleLoader
         web_hooks
         iam_tools
       ],
-      'metadata' => { 'cannot_automatically_be_upgraded_to' => true }
+      metadata: { cannot_automatically_be_upgraded_to: true }
     }
   }.freeze
 
@@ -32,7 +32,7 @@ def load_config
   end
 
   def sort_by_rank(yaml)
-    yaml.sort_by { |_, attributes| Integer(attributes['rank']) }
+    yaml.sort_by { |_, attributes| Integer(attributes[:rank]) }
   end
 
   def convert_to_hash_with_plan_rule_objects(config)
diff --git a/app/lib/signup/impersonation_admin_builder.rb b/app/lib/signup/impersonation_admin_builder.rb
index d4c78f3eb0..69d36fa028 100644
--- a/app/lib/signup/impersonation_admin_builder.rb
+++ b/app/lib/signup/impersonation_admin_builder.rb
@@ -4,11 +4,11 @@ module Signup
   class ImpersonationAdminBuilder
     def self.build(account:)
       config = ThreeScale.config.impersonation_admin
-      username = config['username']
+      username = config[:username]
       impersonation_admin = account.users.new(
         {
           username: username,
-          email: "#{username}+#{account.internal_domain}@#{config['domain']}",
+          email: "#{username}+#{account.internal_domain}@#{config[:domain]}",
           first_name: '3scale',
           last_name: 'Admin',
           state: 'active'
diff --git a/app/lib/stats/base.rb b/app/lib/stats/base.rb
index b6e708a622..c8d907c150 100644
--- a/app/lib/stats/base.rb
+++ b/app/lib/stats/base.rb
@@ -1,5 +1,4 @@
-
-require_dependency 'stats'
+# frozen_string_literal: true
 
 module Stats
   class Base
diff --git a/app/lib/system_name.rb b/app/lib/system_name.rb
index 5fdeee72d1..15e5085996 100644
--- a/app/lib/system_name.rb
+++ b/app/lib/system_name.rb
@@ -59,7 +59,7 @@ def generate_system_name!
   # we can guess a reasonable one.
   #
   def internal_system_name
-    model_name = ActiveModel::Name.new(self.class, self.class.parent)
+    model_name = ActiveModel::Name.new(self.class, self.class.module_parent)
     "#{model_name.param_key}_#{SecureRandom.hex(6)}"
   end
 end
diff --git a/app/lib/three_scale/filter_arguments.rb b/app/lib/three_scale/filter_arguments.rb
index e56424a3c5..928cfe9822 100644
--- a/app/lib/three_scale/filter_arguments.rb
+++ b/app/lib/three_scale/filter_arguments.rb
@@ -1,13 +1,8 @@
 # frozen_string_literal: true
 
 module ThreeScale
-  # This class is used to filter sensitive parameters from hashes inside an array of
-  # arguments. It depends on ActionDispatch::Http::ParameterFilter.
-  #
-  # ActionDispatch::Http::ParameterFilter will be removed in Rails 6.1. After we need to change to
-  # ActiveSupport::ParameterFilter
   class FilterArguments
-    FILTER = ActionDispatch::Http::ParameterFilter.new(Rails.configuration.filter_parameters)
+    FILTER = ActiveSupport::ParameterFilter.new(Rails.configuration.filter_parameters)
 
     def initialize(arguments = [])
       @arguments = arguments.dup
diff --git a/app/lib/three_scale/has_money.rb b/app/lib/three_scale/has_money.rb
index c39c9e399d..141aafa8ec 100644
--- a/app/lib/three_scale/has_money.rb
+++ b/app/lib/three_scale/has_money.rb
@@ -1,4 +1,4 @@
-require_dependency File.dirname(__FILE__) + '/money'
+# frozen_string_literal: true
 
 module ThreeScale
   module HasMoney
diff --git a/app/mailers/account_mailer.rb b/app/mailers/account_mailer.rb
index 193cbe6f9c..f5904b6bcc 100644
--- a/app/mailers/account_mailer.rb
+++ b/app/mailers/account_mailer.rb
@@ -5,8 +5,8 @@ class AccountMailer < ActionMailer::Base
   include Liquid::Assigns
   include CMS::EmailTemplate::MailerExtension
 
-  add_template_helper(SupportEntitlementsHelper)
-  add_template_helper(Finance::InvoicesHelper)
+  helper(SupportEntitlementsHelper)
+  helper(Finance::InvoicesHelper)
 
   def confirmed(account)
     self.provider_account = account.provider_account
diff --git a/app/models/account.rb b/app/models/account.rb
index 4984b625f2..20f1d42d3b 100644
--- a/app/models/account.rb
+++ b/app/models/account.rb
@@ -199,7 +199,7 @@ def has_impersonation_admin?
   end
 
   def find_impersonation_admin
-    users.admins.find_by(username: ThreeScale.config.impersonation_admin['username'])
+    users.admins.find_by(username: ThreeScale.config.impersonation_admin[:username])
   end
 
   # Users of this account + users of all buyer accounts of this account (if it is provider).
diff --git a/app/models/authentication_provider.rb b/app/models/authentication_provider.rb
index 6cc63729a1..484cd8e916 100644
--- a/app/models/authentication_provider.rb
+++ b/app/models/authentication_provider.rb
@@ -150,10 +150,3 @@ def set_defaults
     self.name ||= human_kind.to_s
   end
 end
-
-# to prevent warning: toplevel constant GitHub referenced by AuthenticationProvider::GitHub
-require_dependency 'authentication_provider/github'
-require_dependency 'authentication_provider/keycloak'
-require_dependency 'authentication_provider/auth0'
-require_dependency 'authentication_provider/custom'
-require_dependency 'authentication_provider/redhat_customer_portal'
diff --git a/app/models/cinstance.rb b/app/models/cinstance.rb
index fcfbeeb3c9..ecf5640309 100644
--- a/app/models/cinstance.rb
+++ b/app/models/cinstance.rb
@@ -36,7 +36,7 @@ class Cinstance < Contract
 
   # this has to be before the include Backend::ModelExtensions::Cinstance
   # or callbacks order makes keys not to be saved in backend
-  after_save :create_first_key, on: :create
+  after_create :create_first_key
 
   # before_destroy :refund_fixed_cost
   after_commit :reject_if_pending, :on => :destroy
diff --git a/app/models/concerns/symbolize.rb b/app/models/concerns/symbolize.rb
index b70064e5f5..f3f182a8a4 100644
--- a/app/models/concerns/symbolize.rb
+++ b/app/models/concerns/symbolize.rb
@@ -10,6 +10,12 @@ module Symbolize
   end
 
   module AttributesAccessor
+    def changes
+      ActiveSupport::HashWithIndifferentAccess[
+        mutations_from_database.changed_attribute_names.map { |attr| [attr, attribute_change(attr)] }
+      ]
+    end
+
     def attribute_previous_change(attr)
       __symbolize_changes(attr, super)
     end
diff --git a/app/models/email_configuration.rb b/app/models/email_configuration.rb
index 4185d0fed8..571fbb5e54 100644
--- a/app/models/email_configuration.rb
+++ b/app/models/email_configuration.rb
@@ -18,7 +18,7 @@ class EmailConfiguration < ApplicationRecord
   belongs_to :account, optional: false
   validate :account_is_provider
 
-  before_save :set_tenant_id, on: :create
+  before_save :set_tenant_id
 
   scope :for, ->(search_email) {
     where arel_table[:email].matches(search_email.gsub(/([_%\\])/, '\\\\\\1'), "\\", false)
diff --git a/app/models/finance/billing_strategy.rb b/app/models/finance/billing_strategy.rb
index 7b2af254ea..8f44bc2646 100644
--- a/app/models/finance/billing_strategy.rb
+++ b/app/models/finance/billing_strategy.rb
@@ -420,6 +420,3 @@ def ignoring_find_each_scope(&block)
   extend FindEachFix
   include FindEachFix
 end
-
-require_dependency 'finance/prepaid_billing_strategy'
-require_dependency 'finance/postpaid_billing_strategy'
diff --git a/app/models/invoice.rb b/app/models/invoice.rb
index a375c6ae75..7d85a7e7d4 100644
--- a/app/models/invoice.rb
+++ b/app/models/invoice.rb
@@ -1,7 +1,4 @@
-require_dependency 'pdf/finance/invoice_report_data'
-require_dependency 'pdf/finance/invoice_generator'
-
-require_dependency 'month'
+# frozen_string_literal: true
 
 # TODO: add uniqueness check on provider/buyer/period scope
 #
diff --git a/app/models/service.rb b/app/models/service.rb
index 23b0aac9ce..99615a63f1 100644
--- a/app/models/service.rb
+++ b/app/models/service.rb
@@ -113,7 +113,9 @@ def cinstance
 
     account = user.account
     account_services = (account.provider? ? account : account.provider_account).services
-    account_services.merge(user.forbidden_some_services? ? where(id: user.member_permission_service_ids) : {})
+    self.merge(
+      account_services.merge(user.forbidden_some_services? ? where(id: user.member_permission_service_ids) : {})
+    )
   }
 
   validates :name, presence: true
diff --git a/app/models/service_contract.rb b/app/models/service_contract.rb
index 524bf7aef7..3deb560c85 100644
--- a/app/models/service_contract.rb
+++ b/app/models/service_contract.rb
@@ -1,7 +1,7 @@
 class ServiceContract < Contract
   include Logic::Contracting::ServiceContract
 
-  before_create :accept_on_create, :on => :create, :unless => :live?
+  before_create :accept_on_create, :unless => :live?
 
   before_create :set_service_id
   before_validation :set_service_id
diff --git a/app/models/user.rb b/app/models/user.rb
index 1de559f9db..240fdb5390 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -140,8 +140,8 @@ def self.search_states
 
   scope :latest, -> {limit(5).order(created_at: :desc)}
 
-  scope :but_impersonation_admin, -> { where.has { username != ThreeScale.config.impersonation_admin['username'] } }
-  scope :impersonation_admins, -> { where(username: ThreeScale.config.impersonation_admin['username']) }
+  scope :but_impersonation_admin, -> { where.has { username != ThreeScale.config.impersonation_admin[:username] } }
+  scope :impersonation_admins, -> { where(username: ThreeScale.config.impersonation_admin[:username]) }
 
   scope :admins, -> { where(role: 'admin') }
 
@@ -167,7 +167,7 @@ def self.impersonation_admin
   end
 
   def impersonation_admin?
-    username == ThreeScale.config.impersonation_admin['username']
+    username == ThreeScale.config.impersonation_admin[:username]
   end
 
   def any_sso_authorizations?
diff --git a/app/models/web_hook/event.rb b/app/models/web_hook/event.rb
index ef9173a8c8..4ab36ecb63 100644
--- a/app/models/web_hook/event.rb
+++ b/app/models/web_hook/event.rb
@@ -39,7 +39,7 @@ def model
 
     delegate :logger, to: :Rails
 
-    def has_transactional_callbacks?
+    def trigger_transactional_callbacks?
       true
     end
 
diff --git a/app/observers/message_observer.rb b/app/observers/message_observer.rb
index 587d856c51..9380e7e8b8 100644
--- a/app/observers/message_observer.rb
+++ b/app/observers/message_observer.rb
@@ -1,4 +1,4 @@
-require_dependency 'notification_center'
+require 'notification_center'
 
 class MessageObserver < ActiveRecord::Observer
   observe :cinstance, :service_contract
diff --git a/app/services/users/find_oauth2_user_service.rb b/app/services/users/find_oauth2_user_service.rb
index 55a0960c90..f4c57c9f32 100644
--- a/app/services/users/find_oauth2_user_service.rb
+++ b/app/services/users/find_oauth2_user_service.rb
@@ -1,4 +1,4 @@
-class Users::FindOauth2UserService
+class Users::FindOAuth2UserService
 
   Result = Struct.new(:user, :error_message)
 
diff --git a/app/subscribers/after_commit_subscriber.rb b/app/subscribers/after_commit_subscriber.rb
index 5bdf4e7e90..5aa26deede 100644
--- a/app/subscribers/after_commit_subscriber.rb
+++ b/app/subscribers/after_commit_subscriber.rb
@@ -21,7 +21,7 @@ def rolledback!(*)
       subscriber.after_rollback(event)
     end
 
-    def has_transactional_callbacks?
+    def trigger_transactional_callbacks?
       true
     end
 
diff --git a/app/workers/event_import_worker.rb b/app/workers/event_import_worker.rb
index 0b22edaa5b..e6dac1225c 100644
--- a/app/workers/event_import_worker.rb
+++ b/app/workers/event_import_worker.rb
@@ -1,4 +1,4 @@
-require_dependency 'events/importer'
+# frozen_string_literal: true
 
 class EventImportWorker
   include Sidekiq::Worker
diff --git a/app/workers/last_traffic_worker.rb b/app/workers/last_traffic_worker.rb
index a7894d294f..2b570d2191 100644
--- a/app/workers/last_traffic_worker.rb
+++ b/app/workers/last_traffic_worker.rb
@@ -1,4 +1,4 @@
-require_dependency 'last_traffic'
+# frozen_string_literal: true
 
 class LastTrafficWorker
   include Sidekiq::Worker
diff --git a/app/workers/pdf_report_worker.rb b/app/workers/pdf_report_worker.rb
index b365292ee7..7a61a67b48 100644
--- a/app/workers/pdf_report_worker.rb
+++ b/app/workers/pdf_report_worker.rb
@@ -1,3 +1,5 @@
+# frozen_string_literal: true
+
 class PdfReportWorker
   include Sidekiq::Worker
 
@@ -38,7 +40,3 @@ def perform(service_id, account_id, period, reference)
 
   delegate :logger, to: :Rails
 end
-
-if Rails.application.config.three_scale.daily_weekly_reports_pref
-  require_dependency 'pdf/report'
-end
diff --git a/app/workers/signup_worker.rb b/app/workers/signup_worker.rb
index 377c3c0ec5..0574d8b03c 100644
--- a/app/workers/signup_worker.rb
+++ b/app/workers/signup_worker.rb
@@ -1,4 +1,4 @@
-require_dependency 'notification_center'
+# frozen_string_literal: true
 
 class SignupWorker
   include Sidekiq::Worker
diff --git a/bin/setup b/bin/setup
index a5eca9a71c..df8cf5004c 100755
--- a/bin/setup
+++ b/bin/setup
@@ -1,6 +1,5 @@
 #!/usr/bin/env ruby
 require 'fileutils'
-include FileUtils
 
 # path to your application root.
 APP_ROOT = File.expand_path('..', __dir__)
@@ -9,8 +8,9 @@ def system!(*args)
   system(*args) || abort("\n== Command #{args} failed ==")
 end
 
-chdir APP_ROOT do
-  # This script is a starting point to setup your application.
+FileUtils.chdir APP_ROOT do
+  # This script is a way to setup or update your development environment automatically.
+  # This script is idempotent, so that you can run it at anytime and get an expectable outcome.
   # Add necessary setup steps to this file.
 
   puts '== Installing dependencies =='
@@ -24,7 +24,7 @@ chdir APP_ROOT do
   cp_r 'config/examples/.', 'config/', preserve: true, dereference_root: true
 
   puts "\n== Preparing database =="
-  system! 'bin/rails db:setup'
+  system! 'bin/rails db:prepare'
 
   puts "\n== Removing old logs and tempfiles =="
   system! 'bin/rails log:clear tmp:clear'
diff --git a/config/application.rb b/config/application.rb
index 770791d255..fd2abdf15f 100644
--- a/config/application.rb
+++ b/config/application.rb
@@ -58,29 +58,25 @@ class Application < Rails::Application
     # we do here instead of using initializers because of a Rails 5.1 vs
     # MySQL bug where `rake db:reset` causes ActiveRecord to be loaded
     # before initializers and causes configuration not to be respected.
-    # This is fixed in Rails 5.2
-    config.load_defaults 5.1
+    config.load_defaults 6.0
     config.active_record.belongs_to_required_by_default = false
     config.active_record.include_root_in_json = true
     # Make `form_with` generate non-remote forms. Defaults true in Rails 5.1 to 6.0
+    config.action_view.form_with_generates_remote_forms = false
+    # Make Ruby preserve the timezone of the receiver when calling `to_time`.
+    config.active_support.to_time_preserves_timezone = false
+
+    # Use a modern approved hashing function.
+    # This is the default in Rails 7.0, so can be removed when we upgrade.
+    config.active_support.hash_digest_class = OpenSSL::Digest::SHA256
 
     # Applying the patch for CVE-2022-32224 broke YAML deserialization because some classes are disallowed in the serialized YAML
-    # NOTE: Symbol was later added to enabled classes by default, see https://github.com/rails/rails/pull/45584,
-    # it was added to Rails 6.0.6, 6.1.7, 7.0.4
     config.active_record.yaml_column_permitted_classes = [Symbol, Time, Date, BigDecimal, OpenStruct,
                                                           ActionController::Parameters,
                                                           ActiveSupport::TimeWithZone,
                                                           ActiveSupport::TimeZone,
                                                           ActiveSupport::HashWithIndifferentAccess]
 
-    config.action_view.form_with_generates_remote_forms = false
-
-    # Make Ruby preserve the timezone of the receiver when calling `to_time`.
-    config.active_support.to_time_preserves_timezone = false
-    # Use a modern approved hashing function
-    # config.active_support.hash_digest_class = OpenSSL::Digest::SHA256
-    ActiveSupport::Digest.hash_digest_class = OpenSSL::Digest::SHA256 # option above should work with Rails 6.x
-
 
     # The old config_for gem returns HashWithIndifferentAccess
     # https://github.com/3scale/config_for/blob/master/lib/config_for/config.rb#L16
@@ -182,13 +178,16 @@ def try_config_for(*args)
     # We don't want Rack::Cache to be used
     config.action_dispatch.rack_cache = false
 
-    args = config_for(:cache_store)
-    store_type = args.shift
-    options = args.extract_options!
-    servers = args.flat_map { |arg| arg.split(',') }
-    config.cache_store = [store_type, servers, options]
+    def cache_store_config
+      args = config_for(:cache_store)
+      store_type = args.shift
+      options = args.extract_options!
+      options[:digest_class] ||= Digest::SHA256 if store_type == :mem_cache_store
+      [store_type, *args, options]
+    end
+    config.cache_store = cache_store_config
 
-    # Configure the default encoding used in templates for Ruby 1.9.
+      # Configure the default encoding used in templates for Ruby 1.9.
     config.encoding = "utf-8"
 
     config.web_hooks = ActiveSupport::OrderedOptions.new
diff --git a/config/boot.rb b/config/boot.rb
index 30f5120df6..fd869f358c 100644
--- a/config/boot.rb
+++ b/config/boot.rb
@@ -1,3 +1,5 @@
 ENV['BUNDLE_GEMFILE'] ||= File.expand_path('../Gemfile', __dir__)
 
 require 'bundler/setup' # Set up gems listed in the Gemfile.
+
+require 'bootsnap/setup' unless ENV['RAILS_ENV'] == 'production' # Speed up boot time by caching expensive operations.
diff --git a/config/environments/development.rb b/config/environments/development.rb
index e4fca8dcd7..dce2276783 100644
--- a/config/environments/development.rb
+++ b/config/environments/development.rb
@@ -19,6 +19,9 @@
 
   config.asset_host = config.three_scale.asset_host.presence
 
+  # Match custom domains on development
+  config.hosts << /.+\.localhost/
+
   config.middleware.insert_before ActionDispatch::Static, Rack::Deflater
 
   config.public_file_server.enabled = true
diff --git a/config/environments/test.rb b/config/environments/test.rb
index 15c4ec1581..7026cb64d3 100644
--- a/config/environments/test.rb
+++ b/config/environments/test.rb
@@ -21,6 +21,7 @@
   # config.consider_all_requests_local       = true
   config.consider_all_requests_local       = false
   config.action_controller.perform_caching = false
+  config.cache_store = :null_store
 
   # Raise exceptions instead of rendering exception templates.
   config.action_dispatch.show_exceptions = false
diff --git a/config/initializers/application_controller_renderer.rb b/config/initializers/application_controller_renderer.rb
index f4556db399..89d2efab2b 100644
--- a/config/initializers/application_controller_renderer.rb
+++ b/config/initializers/application_controller_renderer.rb
@@ -1,4 +1,3 @@
-# frozen_string_literal: true
 # Be sure to restart your server when you modify this file.
 
 # ActiveSupport::Reloader.to_prepare do
diff --git a/config/initializers/content_security_policy.rb b/config/initializers/content_security_policy.rb
index d3bcaa5ec8..41c43016f1 100644
--- a/config/initializers/content_security_policy.rb
+++ b/config/initializers/content_security_policy.rb
@@ -19,6 +19,9 @@
 # If you are using UJS then enable automatic nonce generation
 # Rails.application.config.content_security_policy_nonce_generator = -> request { SecureRandom.base64(16) }
 
+# Set the nonce only to specific directives
+# Rails.application.config.content_security_policy_nonce_directives = %w(script-src)
+
 # Report CSP violations to a specified URI
 # For further information see the following documentation:
 # https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Security-Policy-Report-Only
diff --git a/config/initializers/dalli.rb b/config/initializers/dalli.rb
deleted file mode 100644
index 28607126a6..0000000000
--- a/config/initializers/dalli.rb
+++ /dev/null
@@ -1,23 +0,0 @@
-# Patches dalli to use SHA256 checksum instead of MD5.
-# Once we stop supporting Ruby 2.4, we should upgrade dalli
-# and see if any configuration is needed for same effect.
-#
-# key digests were actually fixed with
-# https://github.com/petergoldstein/dalli/commit/74b2625f11ff56dd6f55c7316bc115bc5a29be5f
-
-Dalli::Client.prepend(Module.new do
-  def validate_key(key)
-    raise ArgumentError, "key cannot be blank" if !key || key.length == 0
-    key = key_with_namespace(key)
-    if key.length > 250
-      digest = Digest::SHA256.hexdigest(key)
-      truncated_key_separator = ':md5:'
-      truncated_key_target_size = 249
-      # replicating 3.x logic
-      truncated_key_target_size = truncated_key_target_size + 1 if namespace
-      max_length_before_namespace = truncated_key_target_size - truncated_key_separator.size - digest.size
-      key = "#{key[0, max_length_before_namespace]}#{truncated_key_separator}#{digest}"
-    end
-    return key
-  end
-end)
diff --git a/config/initializers/mime_types.rb b/config/initializers/mime_types.rb
index dc1899682b..3e47d1a9d2 100644
--- a/config/initializers/mime_types.rb
+++ b/config/initializers/mime_types.rb
@@ -2,3 +2,17 @@
 
 # Add new mime types for use in respond_to blocks:
 # Mime::Type.register "text/richtext", :rtf
+
+# Extracted from https://github.com/rails/rails/blob/6-1-stable/actionpack/lib/action_dispatch/http/mime_type.rb#L344-L346
+# Mime::NullType has an odd behaviour in Rails 6 due to the check performed in
+# https://github.com/rails/rails/blob/6-0-stable/actionpack/lib/action_controller/metal/mime_responds.rb#L208-L210
+# where media_type and format are different even though both are Mime::NullType.
+# The to_s method fixes the issue but, unfortunately, it was added only for Rails 6.1+.
+# We may removed this patch once we upgrade Rails to 6.1.
+module Mime
+  class NullType
+    def to_s
+      ''
+    end
+  end
+end
diff --git a/config/initializers/money.rb b/config/initializers/money.rb
index 277219f7e1..5565bb24af 100644
--- a/config/initializers/money.rb
+++ b/config/initializers/money.rb
@@ -1,9 +1,9 @@
-require 'three_scale/conversions'
+require 'three_scale/money_conversions'
 
 ActiveSupport.on_load(:active_record) do
   ActiveRecord::Base.send(:include, ThreeScale::HasMoney)
 end
 
 Rails.application.config.to_prepare do
-  ActionController::Base.helper(ThreeScale::MoneyHelper) if defined?(ActionController)
+  ActionController::Base.helper(ThreeScale::MoneyHelper)
 end
diff --git a/config/initializers/new_framework_defaults_5_2.rb b/config/initializers/new_framework_defaults_5_2.rb
deleted file mode 100644
index c383d072bc..0000000000
--- a/config/initializers/new_framework_defaults_5_2.rb
+++ /dev/null
@@ -1,38 +0,0 @@
-# Be sure to restart your server when you modify this file.
-#
-# This file contains migration options to ease your Rails 5.2 upgrade.
-#
-# Once upgraded flip defaults one by one to migrate to the new default.
-#
-# Read the Guide for Upgrading Ruby on Rails for more info on each option.
-
-# Make Active Record use stable #cache_key alongside new #cache_version method.
-# This is needed for recyclable cache keys.
-# Rails.application.config.active_record.cache_versioning = true
-
-# Use AES-256-GCM authenticated encryption for encrypted cookies.
-# Also, embed cookie expiry in signed or encrypted cookies for increased security.
-#
-# This option is not backwards compatible with earlier Rails versions.
-# It's best enabled when your entire app is migrated and stable on 5.2.
-#
-# Existing cookies will be converted on read then written with the new scheme.
-# Rails.application.config.action_dispatch.use_authenticated_cookie_encryption = true
-
-# Use AES-256-GCM authenticated encryption as default cipher for encrypting messages
-# instead of AES-256-CBC, when use_authenticated_message_encryption is set to true.
-# Rails.application.config.active_support.use_authenticated_message_encryption = true
-
-# Add default protection from forgery to ActionController::Base instead of in
-# ApplicationController.
-# Rails.application.config.action_controller.default_protect_from_forgery = true
-
-# Store boolean values are in sqlite3 databases as 1 and 0 instead of 't' and
-# 'f' after migrating old data.
-# Rails.application.config.active_record.sqlite3.represent_boolean_as_integer = true
-
-# Use SHA-1 instead of MD5 to generate non-sensitive digests, such as the ETag header.
-# Rails.application.config.active_support.use_sha1_digests = true
-
-# Make `form_with` generate id attributes for any generated HTML tags.
-# Rails.application.config.action_view.form_with_generates_ids = true
diff --git a/config/initializers/notifications.rb b/config/initializers/notifications.rb
index 7cd1fb24a9..fd5a6e5769 100644
--- a/config/initializers/notifications.rb
+++ b/config/initializers/notifications.rb
@@ -1 +1 @@
-require_dependency 'tracking_notifications'
+require 'tracking_notifications'
diff --git a/config/initializers/oracle.rb b/config/initializers/oracle.rb
index ab8b28d697..2029f3c75f 100644
--- a/config/initializers/oracle.rb
+++ b/config/initializers/oracle.rb
@@ -13,7 +13,7 @@
     end
 
     ActiveRecord::ConnectionAdapters::OracleEnhancedAdapter.class_eval do
-      # see https://github.com/rails/rails/issues/44114
+      # Remove when https://github.com/rsim/oracle-enhanced/issues/2237 is fixed
       self.use_old_oracle_visitor = true
     end
 
diff --git a/config/initializers/zeitwerk.rb b/config/initializers/zeitwerk.rb
new file mode 100644
index 0000000000..79c0377124
--- /dev/null
+++ b/config/initializers/zeitwerk.rb
@@ -0,0 +1,17 @@
+Rails.autoloaders.main.inflector.inflect(
+  'dsl' => 'DSL',
+  'csrf' => 'CSRF',
+  'sso' => 'SSO',
+  'oauth2' => 'OAuth2',
+  'provider_oauth2' => 'ProviderOAuth2',
+  'find_oauth2_user_service' => 'FindOAuth2UserService',
+  'oauth2_base' => 'OAuth2Base',
+  'xml' => 'XML',
+  'json_representer' => 'JSONRepresenter',
+  'json_validator' => 'JSONValidator',
+  'by_sso_token' => 'BySSOToken'
+)
+
+Rails.autoloaders.main.ignore(
+  'app/lib/forum_support/deprecated/'
+)
diff --git a/db/oracle_schema.rb b/db/oracle_schema.rb
index 991a437c5d..846e82fa68 100644
--- a/db/oracle_schema.rb
+++ b/db/oracle_schema.rb
@@ -2,11 +2,11 @@
 # of editing this file, please use the migrations feature of Active Record to
 # incrementally modify your database, and then regenerate this schema definition.
 #
-# Note that this schema.rb definition is the authoritative source for your
-# database schema. If you need to create the application database on another
-# system, you should be using db:schema:load, not running all the migrations
-# from scratch. The latter is a flawed and unsustainable approach (the more migrations
-# you'll amass, the slower it'll run and the greater likelihood for issues).
+# This file is the source Rails uses to define your schema when running `rails
+# db:schema:load`. When creating a new database, `rails db:schema:load` tends to
+# be faster and is potentially less error prone than running all of your
+# migrations from scratch. Old migrations may fail to apply correctly if those
+# migrations use external dependencies or application code.
 #
 # It's strongly recommended that you check this file into your version control system.
 
diff --git a/db/postgres_schema.rb b/db/postgres_schema.rb
index 41c062b9f1..8b94fb84b7 100644
--- a/db/postgres_schema.rb
+++ b/db/postgres_schema.rb
@@ -2,11 +2,11 @@
 # of editing this file, please use the migrations feature of Active Record to
 # incrementally modify your database, and then regenerate this schema definition.
 #
-# Note that this schema.rb definition is the authoritative source for your
-# database schema. If you need to create the application database on another
-# system, you should be using db:schema:load, not running all the migrations
-# from scratch. The latter is a flawed and unsustainable approach (the more migrations
-# you'll amass, the slower it'll run and the greater likelihood for issues).
+# This file is the source Rails uses to define your schema when running `rails
+# db:schema:load`. When creating a new database, `rails db:schema:load` tends to
+# be faster and is potentially less error prone than running all of your
+# migrations from scratch. Old migrations may fail to apply correctly if those
+# migrations use external dependencies or application code.
 #
 # It's strongly recommended that you check this file into your version control system.
 
diff --git a/db/schema.rb b/db/schema.rb
index 3424168336..e709afc166 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -2,11 +2,11 @@
 # of editing this file, please use the migrations feature of Active Record to
 # incrementally modify your database, and then regenerate this schema definition.
 #
-# Note that this schema.rb definition is the authoritative source for your
-# database schema. If you need to create the application database on another
-# system, you should be using db:schema:load, not running all the migrations
-# from scratch. The latter is a flawed and unsustainable approach (the more migrations
-# you'll amass, the slower it'll run and the greater likelihood for issues).
+# This file is the source Rails uses to define your schema when running `rails
+# db:schema:load`. When creating a new database, `rails db:schema:load` tends to
+# be faster and is potentially less error prone than running all of your
+# migrations from scratch. Old migrations may fail to apply correctly if those
+# migrations use external dependencies or application code.
 #
 # It's strongly recommended that you check this file into your version control system.
 
@@ -126,7 +126,7 @@
     t.bigint "account_id"
     t.bigint "tenant_id"
     t.string "name"
-    t.text "body", limit: 4294967295
+    t.text "body", size: :long
     t.text "description"
     t.boolean "published", default: false
     t.datetime "created_at"
@@ -162,7 +162,7 @@
     t.bigint "tenant_id"
     t.bigint "provider_id"
     t.string "kind"
-    t.text "audited_changes", limit: 16777215
+    t.text "audited_changes", size: :medium
     t.text "comment"
     t.integer "associated_id"
     t.string "associated_type"
@@ -222,7 +222,7 @@
   create_table "backend_apis", options: "ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin", force: :cascade do |t|
     t.string "name", limit: 511, null: false
     t.string "system_name", null: false
-    t.text "description", limit: 16777215
+    t.text "description", size: :medium
     t.string "private_endpoint"
     t.bigint "account_id"
     t.datetime "created_at", null: false
@@ -390,8 +390,8 @@
     t.string "path"
     t.string "title"
     t.string "system_name"
-    t.text "published", limit: 16777215
-    t.text "draft", limit: 16777215
+    t.text "published", size: :medium
+    t.text "draft", size: :medium
     t.boolean "liquid_enabled"
     t.string "content_type"
     t.datetime "created_at"
@@ -418,8 +418,8 @@
     t.string "path"
     t.string "title"
     t.string "system_name"
-    t.text "published", limit: 16777215
-    t.text "draft", limit: 16777215
+    t.text "published", size: :medium
+    t.text "draft", size: :medium
     t.boolean "liquid_enabled"
     t.string "content_type"
     t.datetime "created_at"
@@ -492,7 +492,7 @@
     t.string "stream", null: false
     t.string "event_type", null: false
     t.string "event_id", null: false
-    t.text "metadata", limit: 16777215
+    t.text "metadata", size: :medium
     t.text "data"
     t.datetime "created_at", null: false
     t.bigint "provider_id"
@@ -676,7 +676,7 @@
     t.integer "version"
     t.string "name"
     t.string "slug"
-    t.text "body", limit: 4294967295
+    t.text "body", size: :long
     t.datetime "created_at"
     t.datetime "updated_at"
     t.boolean "published", default: false
@@ -693,7 +693,7 @@
     t.integer "lock_version", default: 0
     t.string "name"
     t.string "slug"
-    t.text "body", limit: 4294967295
+    t.text "body", size: :long
     t.datetime "created_at"
     t.datetime "updated_at"
     t.boolean "published", default: false
@@ -940,7 +940,7 @@
     t.bigint "issuer_id", null: false
     t.string "name"
     t.string "rights"
-    t.text "full_legal", limit: 4294967295
+    t.text "full_legal", size: :long
     t.decimal "cost_per_month", precision: 20, scale: 4, default: "0.0", null: false
     t.integer "trial_period_days"
     t.datetime "created_at"
@@ -968,7 +968,7 @@
   create_table "policies", options: "ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin", force: :cascade do |t|
     t.string "name", null: false
     t.string "version", null: false
-    t.binary "schema", limit: 4294967295, null: false
+    t.binary "schema", size: :long, null: false
     t.bigint "account_id", null: false
     t.bigint "tenant_id"
     t.datetime "created_at"
@@ -1082,7 +1082,7 @@
     t.string "oidc_issuer_endpoint"
     t.bigint "lock_version", default: 0, null: false
     t.string "authentication_method"
-    t.text "policies_config", limit: 16777215
+    t.text "policies_config", size: :medium
     t.string "oidc_issuer_type", default: "keycloak"
     t.string "error_headers_limits_exceeded", default: "text/plain; charset=us-ascii"
     t.integer "error_status_limits_exceeded", default: 429
@@ -1106,7 +1106,7 @@
     t.integer "version", default: 0, null: false
     t.bigint "tenant_id"
     t.string "environment", null: false
-    t.text "content", limit: 16777215, null: false
+    t.text "content", size: :medium, null: false
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
     t.string "hosts", limit: 8192
@@ -1118,7 +1118,7 @@
   create_table "proxy_logs", options: "ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin", force: :cascade do |t|
     t.bigint "provider_id"
     t.bigint "tenant_id"
-    t.text "lua_file", limit: 16777215
+    t.text "lua_file", size: :medium
     t.string "status"
     t.datetime "created_at"
     t.datetime "updated_at"
diff --git a/db/seeds.rb b/db/seeds.rb
index 1ff0832b83..ff1fdb08d0 100644
--- a/db/seeds.rb
+++ b/db/seeds.rb
@@ -172,10 +172,10 @@
   impersonation_admin.signup_type = :minimal
 
   impersonation_admin_config = ThreeScale.config.impersonation_admin
-  impersonation_admin_username = impersonation_admin_config['username']
+  impersonation_admin_username = impersonation_admin_config[:username]
   impersonation_admin.attributes = {
     username: impersonation_admin_username,
-    email: "#{impersonation_admin_username}+#{provider.external_admin_domain}@#{impersonation_admin_config['domain']}",
+    email: "#{impersonation_admin_username}+#{provider.external_admin_domain}@#{impersonation_admin_config[:domain]}",
     first_name: '3scale',
     last_name: 'Admin'
   }
diff --git a/features/step_definitions/provider_steps.rb b/features/step_definitions/provider_steps.rb
index eccd397ee4..b60b192e2c 100644
--- a/features/step_definitions/provider_steps.rb
+++ b/features/step_definitions/provider_steps.rb
@@ -46,7 +46,7 @@ def import_simple_layout(provider)
   step %(a provider "#{provider_name}")
   provider = Account.find_by_org_name(provider_name)
   if provider.admins.impersonation_admins.empty?
-    FactoryBot.create :active_admin, username: ThreeScale.config.impersonation_admin['username'], account: provider
+    FactoryBot.create :active_admin, username: ThreeScale.config.impersonation_admin[:username], account: provider
   end
 end
 
diff --git a/features/support/capybara.rb b/features/support/capybara.rb
index 3c1b9cdaa0..94a7360374 100644
--- a/features/support/capybara.rb
+++ b/features/support/capybara.rb
@@ -28,7 +28,7 @@
   config.raise_server_errors = true
   config.match = :prefer_exact
   config.always_include_port = true
-  config.default_max_wait_time = 2
+  config.default_max_wait_time = 10
 end
 
 # Needed because cucumber-rails requires capybara/cucumber
diff --git a/lib/active_job/serializers/date_time_serializer.rb b/lib/active_job/serializers/date_time_serializer.rb
index 958a3ea8ac..a9076dd45d 100644
--- a/lib/active_job/serializers/date_time_serializer.rb
+++ b/lib/active_job/serializers/date_time_serializer.rb
@@ -1,5 +1,7 @@
 # frozen_string_literal: true
 
+require 'active_job/serializers/time_object_serializer'
+
 module ActiveJob
   module Serializers
     class DateTimeSerializer < TimeObjectSerializer # :nodoc:
diff --git a/lib/developer_portal/app/controllers/developer_portal/accounts/invitee_signups_controller.rb b/lib/developer_portal/app/controllers/developer_portal/accounts/invitee_signups_controller.rb
index 8bd79151c5..d20aad3af8 100644
--- a/lib/developer_portal/app/controllers/developer_portal/accounts/invitee_signups_controller.rb
+++ b/lib/developer_portal/app/controllers/developer_portal/accounts/invitee_signups_controller.rb
@@ -21,7 +21,7 @@ def sso_create
                      request:    request,
                      invitation: @invitation
                    }),
-      procedure: Authentication::Strategy::Oauth2::CreateInvitedUser
+      procedure: Authentication::Strategy::OAuth2::CreateInvitedUser
     )
 
     if signup_user
diff --git a/lib/developer_portal/app/controllers/developer_portal/teapot_controller.rb b/lib/developer_portal/app/controllers/developer_portal/teapot_controller.rb
index bc9f2a28db..1c5f85b508 100644
--- a/lib/developer_portal/app/controllers/developer_portal/teapot_controller.rb
+++ b/lib/developer_portal/app/controllers/developer_portal/teapot_controller.rb
@@ -1,4 +1,4 @@
-require_dependency "developer_portal/application_controller"
+# frozen_string_literal: true
 
 module DeveloperPortal
   class TeapotController < ApplicationController
diff --git a/lib/developer_portal/lib/cms/toolbar.rb b/lib/developer_portal/lib/cms/toolbar.rb
index a2fa2d8039..77769dfc8e 100644
--- a/lib/developer_portal/lib/cms/toolbar.rb
+++ b/lib/developer_portal/lib/cms/toolbar.rb
@@ -39,7 +39,7 @@ def cms_toolbar_enabled?
     return false if @_exception_handled
 
     is_cms_domain = site_account.provider? && !site_account.master? # => buyer domain
-    is_html_content = response.content_type.nil? || response.content_type == 'text/html' #=> only for html content type
+    is_html_content = response.media_type.nil? || response.media_type == 'text/html' #=> only for html content type
 
     return false unless is_cms_domain
     return false unless is_html_content
@@ -68,7 +68,13 @@ def cms_toolbar_with_iframe_html
 
     controller = self
 
-    view = CMS::Toolbar::View.new(lookup_context, cms_toolbar.assigns, controller, [:html])
+    # When on development we want to clear the view cache on every request, this should be automatic, but after
+    # https://github.com/rails/rails/pull/35623 and https://github.com/rails/rails/pull/35629 this no longer works
+    # for hacked views like the +CMS::Toolbar::View+. So we have to manually clear the cache. Otherwise, we'll have
+    # to restart the server after every change in this file.
+    ActionView::LookupContext::DetailsKey.clear unless Rails.env.production?
+
+    view = CMS::Toolbar::View.new(lookup_context, cms_toolbar.assigns, controller)
     view._routes = _routes
     view.render 'shared/cms/toolbar',
                 :site_account => site_account,
diff --git a/lib/developer_portal/lib/liquid/template/fallback_resolver.rb b/lib/developer_portal/lib/liquid/template/fallback_resolver.rb
index 22a87b5690..27908d0ec2 100644
--- a/lib/developer_portal/lib/liquid/template/fallback_resolver.rb
+++ b/lib/developer_portal/lib/liquid/template/fallback_resolver.rb
@@ -1,28 +1,29 @@
+# frozen_string_literal: true
+
 module Liquid
   class Template
     class FallbackResolver < ActionView::FileSystemResolver
-
       def initialize(path = DeveloperPortal::VIEW_PATH)
         super
       end
 
-      def find_templates(name, prefix, partial, details, outside_app_allowed = false)
+      def _find_all(name, prefix, partial, details, key = nil, locals = [])
         path = build_path(name, prefix, partial)
 
         # force just liquid format
         details = details.merge(handlers: [:liquid])
 
-        query(path, details, details[:formats], outside_app_allowed)
+        query(path, details, details[:formats], locals, cache: !!key)
       end
 
       def build_path(name, prefix, partial)
         prefix = prefix ? [prefix] : []
         prefix = ::File.join(*prefix)
         ::Rails.logger.debug { "FallbackResolver: path: #{[name, prefix, partial].inspect}" }
-        super
+        Path.build(name, prefix, partial)
       end
 
-      public :find_templates
+      public :_find_all
     end
   end
 end
diff --git a/lib/developer_portal/lib/liquid/template/fallback_resolver_no_prefix.rb b/lib/developer_portal/lib/liquid/template/fallback_resolver_no_prefix.rb
index 06b615fd21..b5d95f64b5 100644
--- a/lib/developer_portal/lib/liquid/template/fallback_resolver_no_prefix.rb
+++ b/lib/developer_portal/lib/liquid/template/fallback_resolver_no_prefix.rb
@@ -8,15 +8,14 @@ def initialize(path = DeveloperPortal::VIEW_PATH)
         super
       end
 
-      def find_templates(name, prefix, partial, details, outside_app_allowed = false)
+      def _find_all(name, prefix, partial, details, key = nil, locals = [])
         path = build_path(name, prefix = nil, partial)
 
         # force just liquid format
         details = details.merge(handlers: [:liquid])
 
-        query(path, details, details[:formats], outside_app_allowed)
+        query(path, details, details[:formats], locals, cache: !!key)
       end
-
     end
   end
 end
diff --git a/lib/developer_portal/lib/liquid/template/resolver.rb b/lib/developer_portal/lib/liquid/template/resolver.rb
index 1bbc98229c..1f28869b6a 100644
--- a/lib/developer_portal/lib/liquid/template/resolver.rb
+++ b/lib/developer_portal/lib/liquid/template/resolver.rb
@@ -22,14 +22,13 @@ def initialize(scope)
         super()
       end
 
-      def find_templates(name, prefix, partial, _details, _outside_app_allowed = false)
+      def _find_all(name, prefix, partial, details, key = nil, locals = [])
         path = Path.build(name, prefix, partial)
 
         @scope.templates.for_rails_view(path).map do |record|
           Liquid::Template::View.from(record, path, cms)
         end
       end
-
     end
   end
 end
diff --git a/lib/developer_portal/lib/liquid/template/view.rb b/lib/developer_portal/lib/liquid/template/view.rb
index d49b1b0b57..abe8aa138a 100644
--- a/lib/developer_portal/lib/liquid/template/view.rb
+++ b/lib/developer_portal/lib/liquid/template/view.rb
@@ -3,9 +3,17 @@ class Template
     class View < ActionView::Template
       attr_reader :record
 
-      def initialize(source, ident, handler, details)
-        source ||= '' # in case template is nil
-        super
+      def initialize(source = '', identifier, handler, details)
+        super(
+          source,
+          identifier,
+          handler,
+          locals: [],
+          format: nil,
+          variant: details[:variant],
+          virtual_path: details[:virtual_path]
+        )
+
         @record = details.fetch(:record)
       end
 
diff --git a/lib/system/database.rb b/lib/system/database.rb
index 72d38bcbb1..ef4b8fe0d7 100644
--- a/lib/system/database.rb
+++ b/lib/system/database.rb
@@ -14,9 +14,9 @@ def configuration_specification
     def read_configuration_specification
       configurations = Rails.application.config.database_configuration
       resolver = ActiveRecord::ConnectionAdapters::ConnectionSpecification::Resolver.new(configurations)
-      spec = ActiveRecord::ConnectionHandling::DEFAULT_ENV.call.to_sym
+      spec = ActiveRecord::ConnectionHandling::DEFAULT_ENV.call
 
-      resolver.spec(spec)
+      resolver.spec(resolver.configurations[spec])
     end
 
     def adapter
diff --git a/lib/tasks/fixes.rake b/lib/tasks/fixes.rake
index 92811920f6..892e784489 100644
--- a/lib/tasks/fixes.rake
+++ b/lib/tasks/fixes.rake
@@ -23,8 +23,8 @@ namespace :fixes do
   desc "updates impersonation_admin email address"
   task :update_impersonation_admin_email => :environment do
     impersonation_admin_config   = ThreeScale.config.impersonation_admin
-    impersonation_admin_username = impersonation_admin_config['username']
-    impersonation_admin_domain   = impersonation_admin_config['domain']
+    impersonation_admin_username = impersonation_admin_config[:username]
+    impersonation_admin_domain   = impersonation_admin_config[:domain]
 
     users= User.where(email: "#{impersonation_admin_username}@#{impersonation_admin_domain}")
     users.each do | user |
diff --git a/lib/three_scale/conversions.rb b/lib/three_scale/money_conversions.rb
similarity index 84%
rename from lib/three_scale/conversions.rb
rename to lib/three_scale/money_conversions.rb
index 9d38b853c5..1c5f101493 100644
--- a/lib/three_scale/conversions.rb
+++ b/lib/three_scale/money_conversions.rb
@@ -1,14 +1,14 @@
 # frozen_string_literal: true
 
 module ThreeScale
-  module Conversions
+  module MoneyConversions
     def to_has_money(currency, date = nil)
       ThreeScale::Money.new(self, currency, date)
     end
   end
 
   # Enhance numeric types with +to_has_money+ method.
-  Numeric.send(:include, Conversions)
+  Numeric.send(:include, MoneyConversions)
 
   # Enhance String with +to_has_money+ method.
   class ::String
diff --git a/test/functional/buyers/impersonations_controller_test.rb b/test/functional/buyers/impersonations_controller_test.rb
index 353b8e6da2..a7eaaa73ec 100644
--- a/test/functional/buyers/impersonations_controller_test.rb
+++ b/test/functional/buyers/impersonations_controller_test.rb
@@ -26,7 +26,7 @@ def setup
   end
 
   test "should impersonate a provider" do
-    user = FactoryBot.create :active_admin, username: ThreeScale.config.impersonation_admin['username'], :account => @provider
+    user = FactoryBot.create :active_admin, username: ThreeScale.config.impersonation_admin[:username], :account => @provider
     @provider.reload
 
     login_provider master_account
@@ -37,7 +37,7 @@ def setup
   end
 
   test "api mode should return an url to impersonate a provider" do
-    user = FactoryBot.create :active_admin, username: ThreeScale.config.impersonation_admin['username'], :account => @provider
+    user = FactoryBot.create :active_admin, username: ThreeScale.config.impersonation_admin[:username], :account => @provider
     @provider.reload
 
     login_provider master_account
diff --git a/test/functional/developer_portal/admin/account/account_plans_controller_test.rb b/test/functional/developer_portal/admin/account/account_plans_controller_test.rb
index 4c7ccb2504..36de5ed7b5 100644
--- a/test/functional/developer_portal/admin/account/account_plans_controller_test.rb
+++ b/test/functional/developer_portal/admin/account/account_plans_controller_test.rb
@@ -67,7 +67,7 @@ def setup
          provider_key: 'fake', username: 'bob' }
 
     assert_response :forbidden
-    assert_equal 'application/xml', @response.content_type
+    assert_equal 'application/xml', @response.media_type
 
     assert_select 'error', 'provider_key is invalid'
   end
@@ -85,7 +85,7 @@ def setup
          username: 'fake' }
 
     assert_response :forbidden
-    assert_equal 'application/xml', @response.content_type
+    assert_equal 'application/xml', @response.media_type
 
     assert_select 'error', 'username is invalid'
   end
diff --git a/test/functional/developer_portal/signup_controller_test.rb b/test/functional/developer_portal/signup_controller_test.rb
index 888458b479..022f705c0c 100644
--- a/test/functional/developer_portal/signup_controller_test.rb
+++ b/test/functional/developer_portal/signup_controller_test.rb
@@ -35,7 +35,7 @@ class WithDefaultAccountPlan < DeveloperPortal::SignupControllerTest
       session[:authentication_id] = 'A1234'
       session[:authentication_provider] = auth_provider.system_name
       # First check that the confirmation link is send
-      perform_enqueued_jobs(only: ActionMailer::DeliveryJob) do
+      perform_enqueued_jobs(only: ActionMailer::MailDeliveryJob) do
         post :create, params: valid_buyer_params
       end
       assert_response :redirect
@@ -51,7 +51,7 @@ class WithDefaultAccountPlan < DeveloperPortal::SignupControllerTest
       session[:authentication_id] = 'A1234'
       session[:authentication_provider] = auth_provider.system_name
       session[:authentication_email] = valid_buyer_params.dig(:account, :user, :email)
-      perform_enqueued_jobs(only: ActionMailer::DeliveryJob) do
+      perform_enqueued_jobs(only: ActionMailer::MailDeliveryJob) do
         post :create, params: valid_buyer_params
       end
       assert_response :redirect
diff --git a/test/integration/api/sso_tokens_controller_test.rb b/test/integration/api/sso_tokens_controller_test.rb
index eee2e2d1be..e42a64bd5a 100644
--- a/test/integration/api/sso_tokens_controller_test.rb
+++ b/test/integration/api/sso_tokens_controller_test.rb
@@ -38,7 +38,7 @@ def setup
     end
 
     test 'provider_create' do
-      FactoryBot.create(:simple_admin, account: @provider, username: ThreeScale.config.impersonation_admin['username'])
+      FactoryBot.create(:simple_admin, account: @provider, username: ThreeScale.config.impersonation_admin[:username])
       post provider_create_admin_api_sso_tokens_path(format: :json), params: { provider_id: @provider.id, access_token: @access_token.value }
       assert_response :success
 
@@ -48,7 +48,7 @@ def setup
     end
 
     test 'provider_create with expires_in' do
-      FactoryBot.create(:simple_admin, account: @provider, username: ThreeScale.config.impersonation_admin['username'])
+      FactoryBot.create(:simple_admin, account: @provider, username: ThreeScale.config.impersonation_admin[:username])
 
       freeze_time do
         post provider_create_admin_api_sso_tokens_path(format: :json), params: { provider_id: @provider.id, access_token: @access_token.value, expires_in: 60 }
@@ -59,4 +59,3 @@ def setup
     end
   end
 end
-
diff --git a/test/integration/by_sso_token_test.rb b/test/integration/by_sso_token_test.rb
index 1ec5268cfa..d25289b04c 100644
--- a/test/integration/by_sso_token_test.rb
+++ b/test/integration/by_sso_token_test.rb
@@ -10,7 +10,7 @@ def setup
 
   def test_sso_token
     # apicast mapping service use case
-    FactoryBot.create(:active_admin, account: @account, username: ThreeScale.config.impersonation_admin['username'])
+    FactoryBot.create(:active_admin, account: @account, username: ThreeScale.config.impersonation_admin[:username])
     host! Account.master.internal_admin_domain
     post provider_create_admin_api_sso_tokens_path(format: :json), params: { provider_key: @master.api_key, provider_id: @account.id }
     sso_token = JSON.parse(response.body)['sso_token']
diff --git a/test/integration/developer_portal/invitation_signup_test.rb b/test/integration/developer_portal/invitation_signup_test.rb
index e2296d5527..e2dc521a4e 100644
--- a/test/integration/developer_portal/invitation_signup_test.rb
+++ b/test/integration/developer_portal/invitation_signup_test.rb
@@ -3,7 +3,7 @@
 class DeveloperPortal::InvitationSignupTest < ActionDispatch::IntegrationTest
   include System::UrlHelpers.cms_url_helpers
 
-  Oauth2 = Authentication::Strategy::Oauth2
+  OAuth2 = Authentication::Strategy::OAuth2
 
   def setup
     @provider   = FactoryBot.create(:simple_provider)
@@ -23,8 +23,8 @@ def test_show
 
     # sso attributes do exist, sso authorization object should be built
     # and therefore, user password should not be required
-    Oauth2.any_instance.stubs(:authentication_provider).returns(@auth_provider)
-    Oauth2.any_instance.expects(:user_data).returns({ uid: '12345' })
+    OAuth2.any_instance.stubs(:authentication_provider).returns(@auth_provider)
+    OAuth2.any_instance.expects(:user_data).returns({ uid: '12345' })
     get "/auth/invitations/#{@invitation.token}/github/callback"
     assert_response :success
     get invitee_signup_path(invitation_token: @invitation.token)
@@ -63,38 +63,38 @@ def test_builtin_page
 
   def test_auth0_sso_create
     user = FactoryBot.create(:simple_user, account: @buyer)
-    Oauth2.any_instance.expects(:authenticate).returns(user).at_least_once
+    OAuth2.any_instance.expects(:authenticate).returns(user).at_least_once
     get "/auth/invitations/auth0/auth0_ab1234/callback?state=#{@invitation.token}"
     assert_response :redirect
     assert_equal 'Signed up successfully', flash[:notice]
   end
 
   def test_sso_create
-    Oauth2.any_instance.stubs(:authentication_provider).returns(@auth_provider)
-    Oauth2.any_instance.expects(:authenticate).returns(false).at_least_once
+    OAuth2.any_instance.stubs(:authentication_provider).returns(@auth_provider)
+    OAuth2.any_instance.expects(:authenticate).returns(false).at_least_once
     get "/auth/invitations/#{@invitation.token}/github/callback"
     assert_response :success
     assert session[:invitation_sso_uid].blank?
     refute assigns(:user).valid?
 
-    Oauth2.any_instance.expects(:user_data).returns({ uid: '12345' })
+    OAuth2.any_instance.expects(:user_data).returns({ uid: '12345' })
     get "/auth/invitations/#{@invitation.token}/github/callback"
     assert_response :success
     assert_equal '12345', session[:invitation_sso_uid]
     refute assigns(:user).valid?
 
     user = FactoryBot.create(:simple_user, account: @buyer)
-    Oauth2.any_instance.expects(:authenticate).returns(user).at_least_once
+    OAuth2.any_instance.expects(:authenticate).returns(user).at_least_once
     get "/auth/invitations/#{@invitation.token}/github/callback"
     assert_response :redirect
     assert_equal 'Signed up successfully', flash[:notice]
   end
 
   def test_error_sso_create
-    Oauth2.any_instance.stubs(:authentication_provider).returns(@auth_provider)
-    Oauth2.any_instance.expects(:authenticate).returns(false).at_least_once
+    OAuth2.any_instance.stubs(:authentication_provider).returns(@auth_provider)
+    OAuth2.any_instance.expects(:authenticate).returns(false).at_least_once
     error_data = ThreeScale::OAuth2::ErrorData.new(error: 'The code is incorrect or expired.')
-    Oauth2.any_instance.expects(:user_data).returns(error_data)
+    OAuth2.any_instance.expects(:user_data).returns(error_data)
 
     get "/auth/invitations/#{@invitation.token}/github/callback"
     assert_response :success
@@ -103,7 +103,7 @@ def test_error_sso_create
   end
 
   def test_create
-    Oauth2.any_instance.stubs(:authentication_provider).returns(@auth_provider)
+    OAuth2.any_instance.stubs(:authentication_provider).returns(@auth_provider)
 
     assert_difference '@buyer.users.count' do
       post invitee_signup_path(invitation_token: @invitation.token, user: user_valid_params)
diff --git a/test/integration/developer_portal/login_test.rb b/test/integration/developer_portal/login_test.rb
index 284007a29a..ae7d9a3ffe 100644
--- a/test/integration/developer_portal/login_test.rb
+++ b/test/integration/developer_portal/login_test.rb
@@ -82,7 +82,7 @@ def test_create_approval_required
     @provider.authentication_providers.update_all(automatically_approve_accounts: false)
     stub_user_data(uid: 'uid1', email: 'foo@example.com', username: 'foo', org_name: 'company', email_verified: true)
     stub_oauth2_request
-    perform_enqueued_jobs(only: ActionMailer::DeliveryJob) do
+    perform_enqueued_jobs(only: ActionMailer::MailDeliveryJob) do
       post session_path(system_name: @auth.system_name, code: 'example')
     end
     assert_match "Your account isn't active or hasn't been approved yet.", flash[:error]
diff --git a/test/integration/notifications_test.rb b/test/integration/notifications_test.rb
index 3563d928fd..6c2881bb28 100644
--- a/test/integration/notifications_test.rb
+++ b/test/integration/notifications_test.rb
@@ -59,7 +59,7 @@ def setup
       MailDispatchRule.delete_all
 
       @message.save!
-      perform_enqueued_jobs(only: ActionMailer::DeliveryJob) { @message.deliver! }
+      perform_enqueued_jobs(only: ActionMailer::MailDeliveryJob) { @message.deliver! }
 
       @message_recipient = @provider_recipient.received_messages.last
       assert_equal true, @message_recipient.notifiable?
@@ -71,7 +71,7 @@ def setup
       @message.system_operation = @operation
 
       @message.save!
-      perform_enqueued_jobs(only: ActionMailer::DeliveryJob) { @message.deliver! }
+      perform_enqueued_jobs(only: ActionMailer::MailDeliveryJob) { @message.deliver! }
 
       @message_recipient = @provider_recipient.received_messages.last
       assert_equal false, @message_recipient.notifiable?
@@ -82,7 +82,7 @@ def setup
 
       assert_difference ActionMailer::Base.deliveries.method(:count) do
         @message.save!
-        perform_enqueued_jobs(only: ActionMailer::DeliveryJob) { @message.deliver! }
+        perform_enqueued_jobs(only: ActionMailer::MailDeliveryJob) { @message.deliver! }
       end
 
       @message_recipient = @provider_recipient.received_messages.last
@@ -96,7 +96,7 @@ def setup
 
       assert_no_difference ActionMailer::Base.deliveries.method(:count) do
         @message.save!
-        perform_enqueued_jobs(only: ActionMailer::DeliveryJob) { @message.deliver! }
+        perform_enqueued_jobs(only: ActionMailer::MailDeliveryJob) { @message.deliver! }
       end
     end
 
@@ -104,7 +104,7 @@ def setup
       @rule = FactoryBot.create(:mail_dispatch_rule, account: @provider_recipient, dispatch: false, system_operation: @operation)
 
       @message.save!
-      perform_enqueued_jobs(only: ActionMailer::DeliveryJob) { @message.deliver! }
+      perform_enqueued_jobs(only: ActionMailer::MailDeliveryJob) { @message.deliver! }
 
       @message_recipient = @provider_recipient.received_messages.last
       assert_equal @message_recipient.notifiable?, false
@@ -113,7 +113,7 @@ def setup
     test 'notify recipient when operation has no corresponding system operation' do
       @message.update(system_operation: nil)
       @message.save!
-      perform_enqueued_jobs(only: ActionMailer::DeliveryJob) { @message.deliver! }
+      perform_enqueued_jobs(only: ActionMailer::MailDeliveryJob) { @message.deliver! }
 
       @message_recipient = @provider_recipient.received_messages.last
       assert_equal true, @message_recipient.notifiable?
@@ -190,7 +190,7 @@ def setup
     end
 
     test 'be notified' do
-      perform_enqueued_jobs(only: ActionMailer::DeliveryJob) { @buyer.buy! @plan }
+      perform_enqueued_jobs(only: ActionMailer::MailDeliveryJob) { @buyer.buy! @plan }
       assert_includes ActionMailer::Base.deliveries.last.bcc, @admin.email
     end
 
@@ -199,7 +199,7 @@ def setup
       rule = @provider.mail_dispatch_rules.create!(system_operation: op, emails: @admin.email)
       rule.update(dispatch: false)
 
-      perform_enqueued_jobs(only: ActionMailer::DeliveryJob) { @buyer.buy! @plan }
+      perform_enqueued_jobs(only: ActionMailer::MailDeliveryJob) { @buyer.buy! @plan }
 
       assert ActionMailer::Base.deliveries.empty?
     end
@@ -222,7 +222,7 @@ def setup
     test 'notify admins' do
       @mail_rule.update(dispatch: true)
 
-      perform_enqueued_jobs(only: ActionMailer::DeliveryJob) { @buyer.make_pending! }
+      perform_enqueued_jobs(only: ActionMailer::MailDeliveryJob) { @buyer.make_pending! }
 
       assert_includes ActionMailer::Base.deliveries.map(&:bcc).flatten, @admin.email
     end
@@ -230,7 +230,7 @@ def setup
     test 'not notify admins if mail_dispatch_rule denies it' do
       @mail_rule.update(dispatch: false)
 
-      perform_enqueued_jobs(only: ActionMailer::DeliveryJob) { @buyer.make_pending! }
+      perform_enqueued_jobs(only: ActionMailer::MailDeliveryJob) { @buyer.make_pending! }
 
       assert_not_includes ActionMailer::Base.deliveries.map(&:bcc).flatten, @admin.email
     end
diff --git a/test/integration/provider/admin/account/authentication_provider_flow_testing_test.rb b/test/integration/provider/admin/account/authentication_provider_flow_testing_test.rb
index 2f20955b80..4e39607124 100644
--- a/test/integration/provider/admin/account/authentication_provider_flow_testing_test.rb
+++ b/test/integration/provider/admin/account/authentication_provider_flow_testing_test.rb
@@ -18,20 +18,20 @@ def test_flow_testing
   end
 
   def test_flow_testing_callback
-    Authentication::Strategy::ProviderOauth2.any_instance.stubs(:authentication_provider).returns(@auth_provider)
-    Authentication::Strategy::ProviderOauth2.any_instance.expects(:authenticate).returns(nil)
+    Authentication::Strategy::ProviderOAuth2.any_instance.stubs(:authentication_provider).returns(@auth_provider)
+    Authentication::Strategy::ProviderOAuth2.any_instance.expects(:authenticate).returns(nil)
     get provider_admin_account_flow_testing_callback_url(system_name: @auth_provider.system_name)
     assert_nil flash[:success]
 
-    Authentication::Strategy::ProviderOauth2.any_instance.expects(:authenticate).returns(@user)
+    Authentication::Strategy::ProviderOAuth2.any_instance.expects(:authenticate).returns(@user)
     get provider_admin_account_flow_testing_callback_url(system_name: @auth_provider.system_name)
     assert_match 'Authentication flow successfully tested.', flash[:success]
   end
 
   def test_unsuccessful_callback
-    Authentication::Strategy::ProviderOauth2.any_instance.stubs(:authentication_provider).returns(@auth_provider)
-    Authentication::Strategy::ProviderOauth2.any_instance.stubs(:error_message).returns('some oauth error')
-    Authentication::Strategy::ProviderOauth2.any_instance.expects(:authenticate).returns(false)
+    Authentication::Strategy::ProviderOAuth2.any_instance.stubs(:authentication_provider).returns(@auth_provider)
+    Authentication::Strategy::ProviderOAuth2.any_instance.stubs(:error_message).returns('some oauth error')
+    Authentication::Strategy::ProviderOAuth2.any_instance.expects(:authenticate).returns(false)
     get provider_admin_account_flow_testing_callback_url(system_name: @auth_provider.system_name)
     assert_match 'some oauth error', flash[:error]
   end
diff --git a/test/integration/provider/admin/applications/applications_controller_test.rb b/test/integration/provider/admin/applications/applications_controller_test.rb
index 8cd089f9a1..ae270630df 100644
--- a/test/integration/provider/admin/applications/applications_controller_test.rb
+++ b/test/integration/provider/admin/applications/applications_controller_test.rb
@@ -270,7 +270,7 @@ def setup
         Logic::RollingUpdates.expects(skipped?: true).at_least_once
 
         ActionMailer::Base.deliveries = []
-        perform_enqueued_jobs(only: ActionMailer::DeliveryJob) do
+        perform_enqueued_jobs(only: ActionMailer::MailDeliveryJob) do
           put change_plan_provider_admin_application_path(cinstance), params: { cinstance: { plan_id: new_plan.id } }
         end
 
diff --git a/test/integration/sessions_test.rb b/test/integration/sessions_test.rb
index 01034d93e6..4729431ae5 100644
--- a/test/integration/sessions_test.rb
+++ b/test/integration/sessions_test.rb
@@ -13,7 +13,7 @@ def setup
     provider_user = FactoryBot.create(:user, account: @provider)
     provider_user.activate!
 
-    Authentication::Strategy::ProviderOauth2.any_instance.expects(:authenticate).returns(provider_user)
+    Authentication::Strategy::ProviderOAuth2.any_instance.expects(:authenticate).returns(provider_user)
 
     open_session do |session|
       session.host! @provider.external_admin_domain
diff --git a/test/integration/stats/api/applications_test.rb b/test/integration/stats/api/applications_test.rb
index 4813185d51..f9437b4768 100644
--- a/test/integration/stats/api/applications_test.rb
+++ b/test/integration/stats/api/applications_test.rb
@@ -16,7 +16,7 @@ def setup
     }
 
     assert_response :success
-    assert_content_type 'application/json'
+    assert_media_type 'application/json'
 
     response = ActiveSupport::JSON.decode(@response.body)
     assert_equal response["values"], [0] * 25
diff --git a/test/integration/stats/authentication_test.rb b/test/integration/stats/authentication_test.rb
index 5e352b79e3..9bbd3a3c27 100644
--- a/test/integration/stats/authentication_test.rb
+++ b/test/integration/stats/authentication_test.rb
@@ -14,19 +14,19 @@ def setup
     params = { period: 'day', metric_name: 'hits' }
     get usage_stats_data_services_path(@service, format: :json), params: params.merge(provider_key: @provider_account.api_key)
     assert_response :success
-    assert_content_type 'application/json'
+    assert_media_type 'application/json'
 
     token = FactoryBot.create(:access_token, owner: @provider_account.first_admin, scopes: ['stats'])
     get usage_stats_data_services_path(@service, format: :json), params: params.merge(access_token: token.value)
     assert_response :success
-    assert_content_type 'application/json'
+    assert_media_type 'application/json'
   end
 
   test 'access forbidden without authentication' do
     get usage_stats_data_services_path(@service, format: :json), params: { period: 'day', metric_name: "hits" }
 
     assert_response :forbidden
-    assert_content_type 'application/json'
+    assert_media_type 'application/json'
     assert_json 'status' => 'Forbidden'
   end
 
diff --git a/test/integration/stats/clients_test.rb b/test/integration/stats/clients_test.rb
index 70c1050106..56b4572833 100644
--- a/test/integration/stats/clients_test.rb
+++ b/test/integration/stats/clients_test.rb
@@ -37,7 +37,7 @@ def setup
     get usage_stats_api_applications_path(@cinstance, format: :json), params: { period: 'month', metric_name: @metric.system_name, skip_change: false }
 
     assert_response :success
-    assert_content_type 'application/json'
+    assert_media_type 'application/json'
     assert_json "period"=>
       {"name"=>"month",
        "granularity"=>"day",
@@ -78,7 +78,7 @@ def setup
     get usage_response_code_stats_api_applications_path(@cinstance, format: :json), params: { period: 'month', response_code: 200 }
 
     assert_response :success
-    assert_content_type 'application/json'
+    assert_media_type 'application/json'
     assert_json "response_code" => {'code' => '200'},
     "period"=>
       {"name"=>"month",
@@ -101,7 +101,7 @@ def setup
     get usage_response_code_stats_api_applications_path(@cinstance, format: :json), params: { period: 'month', response_code: 404 }
 
     assert_response :success
-    assert_content_type 'application/json'
+    assert_media_type 'application/json'
     assert_json "response_code" => {'code' => '404'},
     "period"=>
       {"name"=>"month",
diff --git a/test/integration/stats/data/backend_apis_controller_test.rb b/test/integration/stats/data/backend_apis_controller_test.rb
index 62346b94f4..ccedfd269f 100644
--- a/test/integration/stats/data/backend_apis_controller_test.rb
+++ b/test/integration/stats/data/backend_apis_controller_test.rb
@@ -18,7 +18,7 @@ def setup
     get usage_stats_data_backend_apis_path(backend_api, format: :json, access_token: access_token.value), params: stats_params
 
     assert_response :success
-    assert_content_type 'application/json'
+    assert_media_type 'application/json'
 
     expected_response = {
       metric: metric.attributes.slice('id', 'system_name', 'unit').merge(name: metric.friendly_name),
diff --git a/test/integration/stats/data/requests_to_api_test.rb b/test/integration/stats/data/requests_to_api_test.rb
index a3409c8fbc..076b6c7559 100644
--- a/test/integration/stats/data/requests_to_api_test.rb
+++ b/test/integration/stats/data/requests_to_api_test.rb
@@ -69,21 +69,21 @@ def setup
     params = { period: 'day', metric_name: "hits", provider_key: @provider_account.api_key }
     get usage_stats_data_applications_path(@application, format: :json), params: params
     assert_response :success
-    assert_content_type 'application/json'
+    assert_media_type 'application/json'
   end
 
   test 'respond on xml for applications' do
     params = { period: 'day', metric_name: "hits", provider_key: @provider_account.api_key }
     get usage_stats_data_applications_path(@application, format: :xml), params: params
     assert_response :success
-    assert_content_type 'application/xml'
+    assert_media_type 'application/xml'
   end
 
   test 'not returning change if asked' do
     params = { period: 'day', metric_name: "hits", provider_key: @provider_account.api_key, skip_change: 'false' }
     get usage_stats_data_applications_path(@application, format: :xml), params: params
     assert_response :success
-    assert_content_type 'application/xml'
+    assert_media_type 'application/xml'
     assert_no_match 'change', @response.body
   end
 
@@ -92,7 +92,7 @@ def setup
     get usage_stats_data_applications_path(@application, format: :json), params: params
     assert_response :success
     assert_not data['change']
-    assert_content_type 'application/json'
+    assert_media_type 'application/json'
   end
 
   test 'returning change if asked' do
@@ -100,21 +100,21 @@ def setup
     get usage_stats_data_applications_path(@application, format: :json), params: params
     assert_response :success
     assert data['change'], "#{data} should have change key"
-    assert_content_type 'application/json'
+    assert_media_type 'application/json'
   end
 
   test 'respond when missing params for applications' do
     params = { period: 'day', provider_key: @provider_account.api_key }
     get usage_stats_data_applications_path(@application, format: :xml), params: params
     assert_response :bad_request
-    assert_content_type 'text/plain'
+    assert_media_type 'text/plain'
   end
 
   test 'response when application not found' do
     params = { period: 'day', metric_name: "hits", provider_key: @provider_account.api_key }
     get usage_stats_data_applications_path(application_id: 'XXX', format: :json), params: params
     assert_response :not_found
-    assert_content_type 'application/json'
+    assert_media_type 'application/json'
     assert_equal '{"error":"Application not found"}', @response.body
   end
 
@@ -122,7 +122,7 @@ def setup
     params = { period: 'day', metric_name: "xxxx", provider_key: @provider_account.api_key }
     get usage_stats_data_applications_path(@application, format: :json), params: params
     assert_response :bad_request
-    assert_content_type 'application/json'
+    assert_media_type 'application/json'
     assert_equal '{"error":"metric xxxx not found"}', @response.body
   end
 
@@ -133,50 +133,50 @@ def setup
     params = { period: 'day', metric_name: "hits", provider_key: @provider_account.api_key }
     get usage_stats_data_services_path(@service, format: :json), params: params
     assert_response :success
-    assert_content_type 'application/json'
+    assert_media_type 'application/json'
   end
 
   test 'respond on json for services in negative timezone and very old times' do
     params = { period: 'month', since: '0150-12-01', timezone: 'Pacific Time (US & Canada)', metric_name: "hits", provider_key: @provider_account.api_key }
     get usage_stats_data_services_path(@service, format: :json), params: params
     assert_response :success
-    assert_content_type 'application/json'
+    assert_media_type 'application/json'
 
     # to trigger the shift > 0 conditions
     get usage_stats_data_services_path(@service, format: :json), params: params.merge(timezone: 'New Delhi')
     assert_response :success
-    assert_content_type 'application/json'
+    assert_media_type 'application/json'
 
     # to trigger the granularity == :month condition
     get usage_stats_data_services_path(@service, format: :json), params: params.merge(period: 'year')
     assert_response :success
-    assert_content_type 'application/json'
+    assert_media_type 'application/json'
 
     # to trigger both the shift > 0 conditions and granularity == :month
     get usage_stats_data_services_path(@service, format: :json), params: params.merge(period: 'year', timezone: 'New Delhi')
     assert_response :success
-    assert_content_type 'application/json'
+    assert_media_type 'application/json'
   end
 
   test 'respond on xml for services' do
     params = { period: 'day', metric_name: "hits", provider_key: @provider_account.api_key }
     get usage_stats_data_services_path(@service, format: :xml), params: params
     assert_response :success
-    assert_content_type 'application/xml'
+    assert_media_type 'application/xml'
   end
 
   test 'respond when missing params for services' do
     params = { period: 'day', provider_key: @provider_account.api_key }
     get usage_stats_data_services_path(@service, format: :xml), params: params
     assert_response :bad_request
-    assert_content_type 'text/plain'
+    assert_media_type 'text/plain'
   end
 
   test 'respond when provided with non-existent metric for services' do
     params = { period: 'day', metric_name: "xxxx", provider_key: @provider_account.api_key }
     get usage_stats_data_services_path(@service, format: :json), params: params
     assert_response :bad_request
-    assert_content_type 'application/json'
+    assert_media_type 'application/json'
     assert_equal '{"error":"metric xxxx not found"}', @response.body
   end
 
@@ -184,7 +184,7 @@ def setup
     params = { period: 'day', metric_name: "hits", provider_key: @provider_account.api_key }
     get usage_stats_data_services_path(service_id: 'XXX', format: :json), params: params
     assert_response :not_found
-    assert_content_type 'application/json'
+    assert_media_type 'application/json'
     assert_equal '{"error":"Service not found"}', @response.body
   end
 
diff --git a/test/integration/stats/services_test.rb b/test/integration/stats/services_test.rb
index 947c1d16e9..ea4e16d001 100644
--- a/test/integration/stats/services_test.rb
+++ b/test/integration/stats/services_test.rb
@@ -22,7 +22,7 @@ def setup
     get usage_response_code_stats_api_services_path(@cinstance.service_id, format: :json), params: { period: 'day', response_code: 200, timezone: 'Madrid', skip_change: false }
 
     assert_response :success
-    assert_content_type 'application/json'
+    assert_media_type 'application/json'
 
     assert_json "period" => { "name" => "day",
                               "granularity" => "hour",
@@ -44,7 +44,7 @@ def setup
     get usage_stats_api_services_path(@cinstance.service_id, format: :json), params: { period: 'day', metric_name: @metric.system_name, timezone: 'Madrid', skip_change: false }
 
     assert_response :success
-    assert_content_type 'application/json'
+    assert_media_type 'application/json'
 
     assert_json "period" => { "name" => "day",
                               "granularity" => "hour",
@@ -73,7 +73,7 @@ def setup
     get usage_stats_api_services_path(@cinstance.service_id, format: :json), params: opts
 
     assert_response :success
-    assert_content_type 'application/json'
+    assert_media_type 'application/json'
 
     assert_json_contains "period" => { "name" => "day",
                                        "granularity" => "hour",
@@ -91,7 +91,7 @@ def setup
     get usage_stats_api_services_path(@cinstance.service_id, format: :json), params: opts
 
     assert_response :success
-    assert_content_type 'application/json'
+    assert_media_type 'application/json'
     assert_json_contains "period" => { "name" => "day",
                                        "granularity" => "hour",
                                        "since" => Time.zone.parse("2009-12-11T07:00:00+12:00"),
@@ -115,7 +115,7 @@ def setup
     get usage_stats_api_services_path(@provider_account.default_service, format: :json), params: { period: 'day', metric_name: @metric.system_name, timezone: 'UTC', skip_change: false }
 
     assert_response :success
-    assert_content_type 'application/json'
+    assert_media_type 'application/json'
 
     assert_json "period" => { "name" => "day",
                               "granularity" => "hour",
@@ -151,7 +151,7 @@ def setup
     get usage_stats_api_services_path(@provider_account.default_service, format: :json), params: { period: 'year', metric_name: @metric.system_name, timezone: 'Madrid', since: "2010-01-01", skip_change: false }
 
     assert_response :success
-    assert_content_type 'application/json'
+    assert_media_type 'application/json'
 
     assert_json "period" => { "name" => "year",
                               "granularity" => "month",
@@ -186,7 +186,7 @@ def setup
     get usage_stats_api_services_path(@provider_account.default_service, format: :json), params: { period: 'year', metric_name: @metric.system_name, timezone: 'Azores', since: "2010-01-01", skip_change: false }
 
     assert_response :success
-    assert_content_type 'application/json'
+    assert_media_type 'application/json'
 
     assert_json "period" => { "name" => "year",
                               "granularity" => "month",
@@ -216,7 +216,7 @@ def setup
     get top_applications_stats_api_services_path(@provider_account.default_service, format: :json), params: { period: :month, metric_name: @metric.system_name }
 
     assert_response :success
-    assert_content_type 'application/json'
+    assert_media_type 'application/json'
     assert_json "period" => { "name" => "month", "since" => "2009-12-01T00:00:00Z", "until" => "2009-12-31T23:59:59Z" },
                 "applications" => [{ "name" =>nil,
                                      "plan" => { "name" => plan.name, "id" => plan.id },
diff --git a/test/integration/user-management-api/nginx_test.rb b/test/integration/user-management-api/nginx_test.rb
index 6e0f930215..329bdbac49 100644
--- a/test/integration/user-management-api/nginx_test.rb
+++ b/test/integration/user-management-api/nginx_test.rb
@@ -19,7 +19,7 @@ def spec_path
   test 'spec' do
     get spec_path, params: { provider_key: @provider.provider_key }
     assert_response :success
-    assert_equal("application/json", @response.content_type)
+    assert_equal("application/json", @response.media_type)
     assert_not_nil @response.body
   end
 
diff --git a/test/test_helpers/assert_content_type.rb b/test/test_helpers/assert_content_type.rb
deleted file mode 100644
index da41d96c81..0000000000
--- a/test/test_helpers/assert_content_type.rb
+++ /dev/null
@@ -1,12 +0,0 @@
-module TestHelpers
-  module AssertContentType
-    private
-
-    def assert_content_type(expected)
-      assert_equal expected, @response.content_type
-    end
-  end
-end
-
-ActionController::TestCase.send(:include, TestHelpers::AssertContentType)
-ActionDispatch::IntegrationTest.send(:include, TestHelpers::AssertContentType)
diff --git a/test/test_helpers/assert_media_type.rb b/test/test_helpers/assert_media_type.rb
new file mode 100644
index 0000000000..ffba8dd83e
--- /dev/null
+++ b/test/test_helpers/assert_media_type.rb
@@ -0,0 +1,12 @@
+module TestHelpers
+  module AssertMediaType
+    private
+
+    def assert_media_type(expected)
+      assert_equal expected, @response.media_type
+    end
+  end
+end
+
+ActionController::TestCase.send(:include, TestHelpers::AssertMediaType)
+ActionDispatch::IntegrationTest.send(:include, TestHelpers::AssertMediaType)
diff --git a/test/unit/abilities/impersonate_test.rb b/test/unit/abilities/impersonate_test.rb
index 5667a98746..0edeff82d5 100644
--- a/test/unit/abilities/impersonate_test.rb
+++ b/test/unit/abilities/impersonate_test.rb
@@ -13,7 +13,7 @@ def setup
     end
 
     test "master admin can impersonate provider accounts" do
-      @provider.admins.first.update_attribute :username, ThreeScale.config.impersonation_admin['username']
+      @provider.admins.first.update_attribute :username, ThreeScale.config.impersonation_admin[:username]
       @provider.reload
 
       user = Account.master.admins.first
@@ -21,7 +21,7 @@ def setup
     end
 
     test "provider admin users cannot impersonate" do
-      @provider.admins.first.update_attribute :username, ThreeScale.config.impersonation_admin['username']
+      @provider.admins.first.update_attribute :username, ThreeScale.config.impersonation_admin[:username]
       @provider.reload
 
       assert_cannot Ability.new(@provider.admins.first), :impersonate, @provider
diff --git a/test/unit/account/states_test.rb b/test/unit/account/states_test.rb
index 23983bada0..646b71453f 100644
--- a/test/unit/account/states_test.rb
+++ b/test/unit/account/states_test.rb
@@ -1,7 +1,7 @@
 require 'test_helper'
 
 class Account::StatesTest < ActiveSupport::TestCase
-  include ActiveJob::TestHelper
+  include ActionMailer::TestHelper
 
   test '.without_suspended' do
     accounts = FactoryBot.create_list(:simple_provider, 2)
@@ -94,14 +94,14 @@ def test_events_when_state_not_changed
 
   test 'enqueues notification email when account is made pending' do
     account = FactoryBot.create(:buyer_account_with_provider)
-    assert_enqueued_with(job: ActionMailer::DeliveryJob, args: ["AccountMailer", "confirmed", "deliver_now", account]) do
+    assert_enqueued_email_with(AccountMailer, :confirmed, args: [account]) do
       account.make_pending!
     end
   end
 
   test 'enqueues notification email when account is rejected' do
     account = FactoryBot.create(:buyer_account_with_provider)
-    assert_enqueued_with(job: ActionMailer::DeliveryJob, args: ["AccountMailer", "rejected", "deliver_now", account]) do
+    assert_enqueued_email_with(AccountMailer, :rejected, args: [account]) do
       account.reject!
     end
   end
@@ -113,7 +113,7 @@ def test_events_when_state_not_changed
     account.buy! FactoryBot.create(:account_plan, :approval_required => true)
     account.reload
 
-    assert_enqueued_with(job: ActionMailer::DeliveryJob, args: ["AccountMailer", "approved", "deliver_now", account]) do
+    assert_enqueued_email_with(AccountMailer, :approved, args: [account]) do
       account.approve!
     end
 
@@ -123,7 +123,7 @@ def test_events_when_state_not_changed
     AccountMailer.any_instance.expects(:approved).never
 
     account = FactoryBot.create(:pending_account)
-    assert_no_enqueued_jobs(only: ActionMailer::DeliveryJob) do
+    assert_no_enqueued_jobs(only: ActionMailer::MailDeliveryJob) do
       account.approve!
     end
   end
diff --git a/test/unit/apicast/provider_source_test.rb b/test/unit/apicast/provider_source_test.rb
index 2f1c663de3..d36f12dea2 100644
--- a/test/unit/apicast/provider_source_test.rb
+++ b/test/unit/apicast/provider_source_test.rb
@@ -32,7 +32,7 @@ def test_services
 
     service.stubs(updated_at: Time.now)
     service_attributes =  @source.attributes_for_proxy['services'][0]
-    assert_equal service.updated_at, service_attributes['updated_at']
+    assert_equal service.updated_at.iso8601, service_attributes['updated_at']
 
     assert proxy_attributes = services.first.proxy
 
@@ -60,4 +60,3 @@ def test_policies_with_default_apicast_policy
     assert_nil @source.attributes_for_proxy['services'][0]['proxy']['policies_config']
   end
 end
-
diff --git a/test/unit/authentication/strategy/oauth2_test.rb b/test/unit/authentication/strategy/oauth2_test.rb
index d1c36349b4..2135170945 100644
--- a/test/unit/authentication/strategy/oauth2_test.rb
+++ b/test/unit/authentication/strategy/oauth2_test.rb
@@ -1,6 +1,6 @@
 require 'test_helper'
 
-class Authentication::Strategy::Oauth2Test < ActiveSupport::TestCase
+class Authentication::Strategy::OAuth2Test < ActiveSupport::TestCase
 
   setup do
     @provider = FactoryBot.create(:simple_provider)
@@ -219,7 +219,7 @@ class SsoSignupTest < ActiveSupport::TestCase
       user_data = valid_user_data
       client.stubs(authenticate!: user_data)
       ThreeScale::OAuth2::Client.expects(:build).with(authentication_provider).returns(client).once
-      perform_enqueued_jobs(only: ActionMailer::DeliveryJob) do
+      perform_enqueued_jobs(only: ActionMailer::MailDeliveryJob) do
         assert_difference(User.method(:count), +1) do
           result = authentication_strategy.authenticate({
                                                           system_name: authentication_provider.system_name,
@@ -251,7 +251,7 @@ class SsoSignupTest < ActiveSupport::TestCase
       client.stubs(authenticate!: user_data)
       ThreeScale::OAuth2::Client.expects(:build).with(authentication_provider).returns(client).once
 
-      perform_enqueued_jobs(only: ActionMailer::DeliveryJob) do
+      perform_enqueued_jobs(only: ActionMailer::MailDeliveryJob) do
         assert_difference(User.method(:count), +1) do
           result = authentication_strategy.authenticate({
                                                           system_name: authentication_provider.system_name,
@@ -324,7 +324,7 @@ class SsoSignupTest < ActiveSupport::TestCase
                                                         code: '1234',
                                                         request: mock_request,
                                                         invitation: invitation
-                                                      }, procedure: Authentication::Strategy::Oauth2::CreateInvitedUser)
+                                                      }, procedure: Authentication::Strategy::OAuth2::CreateInvitedUser)
 
         assert_instance_of User, result
         assert_equal result.email, user_data[:email]
diff --git a/test/unit/authentication/strategy/provider_oauth2_test.rb b/test/unit/authentication/strategy/provider_oauth2_test.rb
index e5c01f2902..1f72a2c2ff 100644
--- a/test/unit/authentication/strategy/provider_oauth2_test.rb
+++ b/test/unit/authentication/strategy/provider_oauth2_test.rb
@@ -1,6 +1,6 @@
 require 'test_helper'
 
-class Authentication::Strategy::ProviderOauth2Test < ActiveSupport::TestCase
+class Authentication::Strategy::ProviderOAuth2Test < ActiveSupport::TestCase
 
   setup do
     @provider = FactoryBot.create(:simple_provider)
@@ -209,7 +209,7 @@ class SsoSignupTest < ActiveSupport::TestCase
       ThreeScale::OAuth2::Client.expects(:build).with(authentication_provider).returns(client).once
 
       deliveries = ActionMailer::Base.deliveries
-      perform_enqueued_jobs(only: ActionMailer::DeliveryJob) do
+      perform_enqueued_jobs(only: ActionMailer::MailDeliveryJob) do
 
         assert_difference(User.method(:count), +1) do
 
@@ -249,7 +249,7 @@ class SsoSignupTest < ActiveSupport::TestCase
           code:        '1234',
           request:     mock_request,
           invitation:  invitation
-        }, procedure:  Authentication::Strategy::Oauth2::CreateInvitedUser)
+        }, procedure:  Authentication::Strategy::OAuth2::CreateInvitedUser)
 
         assert_instance_of User, result
         assert_equal result.email, user_data[:email]
diff --git a/test/unit/cache_store_test.rb b/test/unit/cache_store_test.rb
new file mode 100644
index 0000000000..1463c9bfa3
--- /dev/null
+++ b/test/unit/cache_store_test.rb
@@ -0,0 +1,136 @@
+require 'test_helper'
+
+class CacheStoreTest < ActionView::TestCase
+
+  test ':null_store can be set as cache store' do
+    # cache_store.yml
+    # ---
+    # test:
+    #   - :null_store
+    System::Application.any_instance.expects(:config_for).with(:cache_store).returns([:null_store])
+
+    cache = ActiveSupport::Cache.lookup_store(*System::Application.cache_store_config)
+
+    assert_equal ActiveSupport::Cache::NullStore, cache.class
+  end
+
+  test ':memory_store can be set as cache store' do
+    # cache_store.yml:
+    # ---
+    # test:
+    #   - :memory_store
+    #   - :size: 5000
+    options = { size: 5000 }
+    System::Application.any_instance.expects(:config_for).with(:cache_store).returns([:memory_store, options])
+
+    cache = ActiveSupport::Cache.lookup_store(*System::Application.cache_store_config)
+
+    assert_equal ActiveSupport::Cache::MemoryStore, cache.class
+    assert_equal options, cache.options
+  end
+
+  test ':file_store can be set as cache store' do
+    # cache_store.yml
+    # ---
+    # test:
+    #   - :file_store
+    #   - /tmp/test-file-store
+    path = '/tmp/test-file-store'
+    System::Application.any_instance.expects(:config_for).with(:cache_store).returns([:file_store, path])
+
+    cache = ActiveSupport::Cache.lookup_store(*System::Application.cache_store_config)
+
+    assert_equal ActiveSupport::Cache::FileStore, cache.class
+    assert_equal path, cache.cache_path
+  end
+
+  test ':mem_cache_store can be set as cache store' do
+    # cache_store.yml
+    # ---
+    # test:
+    #   - :mem_cache_store
+    #   - localhost:11211
+    server = 'localhost:11211'
+    System::Application.any_instance.expects(:config_for).with(:cache_store).returns([:mem_cache_store, server])
+
+    cache = ActiveSupport::Cache.lookup_store(*System::Application.cache_store_config)
+
+    assert_equal ActiveSupport::Cache::MemCacheStore, cache.class
+    assert_equal server, cache.stats.keys.first
+  end
+
+  test ':mem_cache_store accepts multiple servers in a string' do
+    # cache_store.yml
+    # ---
+    # test:
+    #   - :mem_cache_store
+    #   - localhost:11211,127.0.0.1:11211,3scale.localhost:11211
+    servers = 'localhost:11211,127.0.0.1:11211,3scale.localhost:11211'
+    System::Application.any_instance.expects(:config_for).with(:cache_store).returns([:mem_cache_store, servers])
+
+    cache = ActiveSupport::Cache.lookup_store(*System::Application.cache_store_config)
+
+    assert_equal ActiveSupport::Cache::MemCacheStore, cache.class
+    assert_same_elements servers.split(','), cache.stats.keys
+  end
+
+  test ':mem_cache_store accepts multiple servers in a list' do
+    # cache_store.yml
+    # ---
+    # test:
+    #   - :mem_cache_store
+    #   - localhost:11211
+    #   - 127.0.0.1:11211
+    #   - 3scale.localhost:11211
+    servers = %w[localhost:11211 127.0.0.1:11211 3scale.localhost:11211]
+    System::Application.any_instance.expects(:config_for).with(:cache_store).returns([:mem_cache_store, servers])
+
+    cache = ActiveSupport::Cache.lookup_store(*System::Application.cache_store_config)
+
+    assert_equal ActiveSupport::Cache::MemCacheStore, cache.class
+    assert_same_elements servers, cache.stats.keys
+  end
+
+  test ':mem_cache_store sets SHA256 as default digest algorithm' do
+    # cache_store.yml
+    # ---
+    # test:
+    #   - :mem_cache_store
+    System::Application.any_instance.expects(:config_for).with(:cache_store).returns([:mem_cache_store])
+
+    cache = ActiveSupport::Cache.lookup_store(*System::Application.cache_store_config)
+
+    assert_equal ActiveSupport::Cache::MemCacheStore, cache.class
+    assert_equal({ digest_class: Digest::SHA256 }, cache.options)
+  end
+
+  test ':mem_cache_store allows overwriting the default digest algorithm' do
+    # cache_store.yml
+    # ---
+    # test:
+    #   - :mem_cache_store
+    #   - :digest_class: !ruby/class Digest::SHA1
+    options = { digest_class: Digest::SHA1 }
+    System::Application.any_instance.expects(:config_for).with(:cache_store).returns([:mem_cache_store, options])
+
+    cache = ActiveSupport::Cache.lookup_store(*System::Application.cache_store_config)
+
+    assert_equal ActiveSupport::Cache::MemCacheStore, cache.class
+    assert_equal options, cache.options
+  end
+
+  test ':redis_cache_store can be set as cache store' do
+    # cache_store.yml
+    # ---
+    # test:
+    #   - :redis_cache_store
+    #   - :url: redis://localhost:6379
+    options = { url: 'redis://localhost:6379' }
+    System::Application.any_instance.expects(:config_for).with(:cache_store).returns([:redis_cache_store, options])
+
+    cache = ActiveSupport::Cache.lookup_store(*System::Application.cache_store_config)
+
+    assert_equal ActiveSupport::Cache::RedisCacheStore, cache.class
+    assert_equal options, cache.redis_options
+  end
+end
diff --git a/test/unit/cinstance_test.rb b/test/unit/cinstance_test.rb
index b00edc1ee8..ddd8b34131 100644
--- a/test/unit/cinstance_test.rb
+++ b/test/unit/cinstance_test.rb
@@ -781,7 +781,7 @@ class SuspendTest < ActiveSupport::TestCase
   test 'email the buyer if configured so' do
     FactoryBot.create(:mail_dispatch_rule, system_operation: SystemOperation.for('app_suspended'), account: @cinstance.provider_account)
 
-    perform_enqueued_jobs(only: ActionMailer::DeliveryJob) { @cinstance.suspend! }
+    perform_enqueued_jobs(only: ActionMailer::MailDeliveryJob) { @cinstance.suspend! }
 
     #TODO: write some email assertion helper?
     assert mail = ActionMailer::Base.deliveries.last, 'missing email'
diff --git a/test/unit/db/seeds_test.rb b/test/unit/db/seeds_test.rb
index 97fb0afcac..5288c36d77 100644
--- a/test/unit/db/seeds_test.rb
+++ b/test/unit/db/seeds_test.rb
@@ -133,8 +133,8 @@ def teardown
     assert impersonation_user.admin?
     assert impersonation_user.active?
     assert impersonation_user.activated_at.present?
-    assert_equal impersonation_admin_config['username'], impersonation_user.username
-    assert_equal "#{impersonation_admin_config['username']}+#{tenant_account.internal_admin_domain}@#{impersonation_admin_config['domain']}", impersonation_user.email
+    assert_equal impersonation_admin_config[:username], impersonation_user.username
+    assert_equal "#{impersonation_admin_config[:username]}+#{tenant_account.internal_admin_domain}@#{impersonation_admin_config[:domain]}", impersonation_user.email
     assert_equal '3scale', impersonation_user.first_name
     assert_equal 'Admin', impersonation_user.last_name
 
diff --git a/test/unit/events/importers/alert_importer_test.rb b/test/unit/events/importers/alert_importer_test.rb
index b0a7d9622f..afb540fd75 100644
--- a/test/unit/events/importers/alert_importer_test.rb
+++ b/test/unit/events/importers/alert_importer_test.rb
@@ -88,7 +88,7 @@ def import_events(events = @events)
     })
 
     ActionMailer::Base.deliveries = []
-    perform_enqueued_jobs(only: ActionMailer::DeliveryJob) do
+    perform_enqueued_jobs(only: ActionMailer::MailDeliveryJob) do
       import_events
     end
 
diff --git a/test/unit/liquid/tags/sort_link_test.rb b/test/unit/liquid/tags/sort_link_test.rb
index 92cef20286..55e262c2be 100644
--- a/test/unit/liquid/tags/sort_link_test.rb
+++ b/test/unit/liquid/tags/sort_link_test.rb
@@ -21,7 +21,7 @@ class Liquid::Tags::SortLinkTest < ActiveSupport::TestCase
     request.parameters[:controller] = controller.controller_path
     request.parameters[:application_id] = '1'
     controller.stubs(request: request)
-    _view = ActionView::Base.new('app/views', {}, controller)
+    _view = ActionView::Base.new(ActionView::LookupContext.new('app/views'), {}, controller)
 
     context = Liquid::Context.new
     context.registers[:controller] = controller
@@ -38,7 +38,7 @@ class Liquid::Tags::SortLinkTest < ActiveSupport::TestCase
     request = ActionDispatch::TestRequest.create
     request.parameters[:controller] = controller.controller_path
     controller.stubs(request: request)
-    _view = ActionView::Base.new('app/views', {}, controller)
+    _view = ActionView::Base.new(ActionView::LookupContext.new('app/views'), {}, controller)
 
     context = Liquid::Context.new
     context.registers[:controller] = controller
@@ -48,4 +48,3 @@ class Liquid::Tags::SortLinkTest < ActiveSupport::TestCase
     assert_nil rendered
   end
 end
-
diff --git a/test/unit/logic/plan_changes_test.rb b/test/unit/logic/plan_changes_test.rb
index 57474e066a..51ea949916 100644
--- a/test/unit/logic/plan_changes_test.rb
+++ b/test/unit/logic/plan_changes_test.rb
@@ -51,7 +51,7 @@ def setup
 
   test '#buyer_changes_plan! - :request' do
     @plan.issuer.stubs(plan_change_permission: :request)
-    perform_enqueued_jobs(only: ActionMailer::DeliveryJob) do
+    perform_enqueued_jobs(only: ActionMailer::MailDeliveryJob) do
       @app.buyer_changes_plan!(@new_plan)
     end
 
@@ -63,7 +63,7 @@ def setup
     @plan.issuer.stubs(plan_change_permission: :credit_card)
     @app.user_account.stubs(:credit_card_stored? => false)
 
-    perform_enqueued_jobs(only: ActionMailer::DeliveryJob) do
+    perform_enqueued_jobs(only: ActionMailer::MailDeliveryJob) do
       @app.buyer_changes_plan!(@new_plan)
     end
 
@@ -75,7 +75,7 @@ def setup
     @plan.issuer.stubs(plan_change_permission: :credit_card)
     @app.user_account.stubs(:credit_card_stored? => true)
 
-    perform_enqueued_jobs(only: ActionMailer::DeliveryJob) do
+    perform_enqueued_jobs(only: ActionMailer::MailDeliveryJob) do
       @app.buyer_changes_plan!(@new_plan)
     end
 
@@ -88,7 +88,7 @@ def setup
     @plan.issuer.stubs(plan_change_permission: :request_credit_card)
     @app.user_account.stubs(:credit_card_stored? => true)
 
-    perform_enqueued_jobs(only: ActionMailer::DeliveryJob) do
+    perform_enqueued_jobs(only: ActionMailer::MailDeliveryJob) do
       @app.buyer_changes_plan!(@new_plan)
     end
 
@@ -101,7 +101,7 @@ def setup
     @plan.issuer.stubs(plan_change_permission: :request_credit_card)
     @app.user_account.stubs(:credit_card_stored? => false)
 
-    perform_enqueued_jobs(only: ActionMailer::DeliveryJob) do
+    perform_enqueued_jobs(only: ActionMailer::MailDeliveryJob) do
       msg = @app.buyer_changes_plan!(@new_paid_plan)
 
       assert_equal "Please enter your credit card before changing the plan.", msg
@@ -114,7 +114,7 @@ def setup
     @plan.issuer.stubs(plan_change_permission: :request_credit_card)
     @app.user_account.stubs(:credit_card_stored? => false)
 
-    perform_enqueued_jobs(only: ActionMailer::DeliveryJob) do
+    perform_enqueued_jobs(only: ActionMailer::MailDeliveryJob) do
       msg = @app.buyer_changes_plan!(@new_plan)
 
       assert_equal "Plan change was successful.", msg
diff --git a/test/unit/message_test.rb b/test/unit/message_test.rb
index 76ec851ffb..f2c2157f0e 100644
--- a/test/unit/message_test.rb
+++ b/test/unit/message_test.rb
@@ -47,7 +47,7 @@ class MessageTest < ActiveSupport::TestCase
 
     message = Message.create!(sender: sender, to: recipients,
                               subject: 'hello', body: "what's up?")
-    perform_enqueued_jobs(only: ActionMailer::DeliveryJob) { message.deliver! }
+    perform_enqueued_jobs(only: ActionMailer::MailDeliveryJob) { message.deliver! }
 
     assert delivery = ActionMailer::Base.deliveries.first
     assert_equal delivery['from'].value, Rails.configuration.three_scale.noreply_email
@@ -86,7 +86,7 @@ class MessageTest < ActiveSupport::TestCase
     ActionMailer::Base.deliveries = []
 
     message = Message.create!(sender: sender, to: recipients, subject: 'hello', body: "what's up?")
-    perform_enqueued_jobs(only: ActionMailer::DeliveryJob) { message.deliver! }
+    perform_enqueued_jobs(only: ActionMailer::MailDeliveryJob) { message.deliver! }
 
     assert delivery = ActionMailer::Base.deliveries.first
     assert_equal delivery['from'].value, sender.from_email
diff --git a/test/unit/messengers/plans_messenger_test.rb b/test/unit/messengers/plans_messenger_test.rb
index 7d330879b2..587c9b24b2 100644
--- a/test/unit/messengers/plans_messenger_test.rb
+++ b/test/unit/messengers/plans_messenger_test.rb
@@ -10,7 +10,7 @@ class PlansMessengerTest < ActiveSupport::TestCase
   test '#plan_change_request' do
     cinstance = FactoryBot.create(:cinstance)
     plan = FactoryBot.create(:account_plan)
-    perform_enqueued_jobs(only: ActionMailer::DeliveryJob) do
+    perform_enqueued_jobs(only: ActionMailer::MailDeliveryJob) do
       PlansMessenger.plan_change_request(cinstance, plan).deliver
     end
 
diff --git a/test/unit/plan_rule_loader_test.rb b/test/unit/plan_rule_loader_test.rb
index 87bc78f7b9..363ce6a38a 100644
--- a/test/unit/plan_rule_loader_test.rb
+++ b/test/unit/plan_rule_loader_test.rb
@@ -4,7 +4,7 @@
 
 class PlanRuleLoaderTest < ActiveSupport::TestCase
   def given_plan_rules_config(config)
-    ThreeScale.config.stubs(:plan_rules).returns(config)
+    ThreeScale.config.stubs(:plan_rules).returns(HashWithIndifferentAccess.new(config))
   end
 
   class LoadErrorTest < PlanRuleLoaderTest
diff --git a/test/unit/services/users/find_oauth2_user_service_test.rb b/test/unit/services/users/find_oauth2_user_service_test.rb
index 2aa987e592..9e4e03615d 100644
--- a/test/unit/services/users/find_oauth2_user_service_test.rb
+++ b/test/unit/services/users/find_oauth2_user_service_test.rb
@@ -1,6 +1,6 @@
 require 'test_helper'
 
-class Users::FindOauth2UserServiceTest < ActiveSupport::TestCase
+class Users::FindOAuth2UserServiceTest < ActiveSupport::TestCase
 
   UsersDouble = Class.new(ActiveRecord::Relation)
 
@@ -91,6 +91,6 @@ def relation
   end
 
   def service
-    Users::FindOauth2UserService
+    Users::FindOAuth2UserService
   end
 end
diff --git a/test/unit/signup/account_manager_test.rb b/test/unit/signup/account_manager_test.rb
index 827b1c8bbc..b9139162ce 100644
--- a/test/unit/signup/account_manager_test.rb
+++ b/test/unit/signup/account_manager_test.rb
@@ -44,7 +44,7 @@ class ProviderAccountManagerTest < Signup::AccountManagerTest
         assert_equal :admin, user.role
 
         # impersonation_admin user is also created with the right attributes
-        assert_equal "#{ThreeScale.config.impersonation_admin['username']}+#{account.internal_domain}@#{imp_config['domain']}", impersonation_user.email
+        assert_equal "#{ThreeScale.config.impersonation_admin[:username]}+#{account.internal_domain}@#{imp_config[:domain]}", impersonation_user.email
         assert_equal '3scale', impersonation_user.first_name
         assert_equal 'Admin', impersonation_user.last_name
 
diff --git a/test/unit/signup/impersonation_admin_builder_test.rb b/test/unit/signup/impersonation_admin_builder_test.rb
index e4b3241367..d6faedd713 100644
--- a/test/unit/signup/impersonation_admin_builder_test.rb
+++ b/test/unit/signup/impersonation_admin_builder_test.rb
@@ -8,10 +8,10 @@ class ImpersonationAdminBuilderTest < ActiveSupport::TestCase
       user_returned = Signup::ImpersonationAdminBuilder.build(account: account)
       user_returned.save!
       config = ThreeScale.config.impersonation_admin
-      username  = config['username']
+      username  = config[:username]
       user_db = User.find_by!(username: username)
       assert_equal user_returned, user_db
-      assert_equal "#{username}+#{account.internal_domain}@#{config['domain']}", user_db.email
+      assert_equal "#{username}+#{account.internal_domain}@#{config[:domain]}", user_db.email
       assert_equal '3scale', user_db.first_name
       assert_equal 'Admin', user_db.last_name
       assert_equal 'active', user_db.state
diff --git a/test/unit/three_scale/analytics/account_classifier_test.rb b/test/unit/three_scale/analytics/account_classifier_test.rb
index 3b95a73cc2..fa1c86e116 100644
--- a/test/unit/three_scale/analytics/account_classifier_test.rb
+++ b/test/unit/three_scale/analytics/account_classifier_test.rb
@@ -7,7 +7,7 @@ def classifier(user_attributes = {})
     provider = FactoryBot.build_stubbed(:provider_account)
     provider.stubs(:users).returns([
                                        FactoryBot.build_stubbed(:admin,
-                                                                 username: ThreeScale.config.impersonation_admin['username']),
+                                                                 username: ThreeScale.config.impersonation_admin[:username]),
                                        FactoryBot.build_stubbed(:admin, user_attributes)
                                    ])
 
@@ -25,10 +25,10 @@ def test_account_type
     assert_equal 'Customer', classifier(email: 'user@example.net', username: 'user').account_type
 
     impersonation_admin_config = ThreeScale.config.impersonation_admin
-    impersonation_admin_username = impersonation_admin_config['username']
+    impersonation_admin_username = impersonation_admin_config[:username]
     assert_equal 'Internal', classifier(email: 'user@example.net', username: impersonation_admin_username).account_type
-    assert_equal 'Customer', classifier(email: "user@#{impersonation_admin_config['domain']}", username: 'user').account_type
-    assert_equal 'Internal', classifier(email: "user@#{impersonation_admin_config['domain']}", username: impersonation_admin_username).account_type
+    assert_equal 'Customer', classifier(email: "user@#{impersonation_admin_config[:domain]}", username: 'user').account_type
+    assert_equal 'Internal', classifier(email: "user@#{impersonation_admin_config[:domain]}", username: impersonation_admin_username).account_type
 
     assert_equal 'Customer', classifier(email: nil, username: nil).account_type
     assert_equal 'Customer', classifier(email: 'user@example.com', username: nil).account_type
diff --git a/test/unit/three_scale/analytics/user_classifier_test.rb b/test/unit/three_scale/analytics/user_classifier_test.rb
index 82e5c3bb6c..1b2c281a99 100644
--- a/test/unit/three_scale/analytics/user_classifier_test.rb
+++ b/test/unit/three_scale/analytics/user_classifier_test.rb
@@ -24,11 +24,11 @@ def test_has_3scale_email?
   def test_is_impersonation_admin?
     refute classifier(username: 'foo').is_impersonation_admin?
 
-    assert classifier(username: ThreeScale.config.impersonation_admin['username']).is_impersonation_admin?
+    assert classifier(username: ThreeScale.config.impersonation_admin[:username]).is_impersonation_admin?
   end
 
   def test_is_3scale?
-    impersonation_admin_username = ThreeScale.config.impersonation_admin['username']
+    impersonation_admin_username = ThreeScale.config.impersonation_admin[:username]
     refute classifier(email: 'foo@example.com', username: 'foo').is_3scale?
     assert classifier(email: 'foo@example.com', username: impersonation_admin_username).is_3scale?
     assert classifier(email: 'foo@3scale.net',  username: impersonation_admin_username).is_3scale?
@@ -44,7 +44,7 @@ def test_is_guest?
   end
 
   def test_user_type
-    impersonation_admin_username = ThreeScale.config.impersonation_admin['username']
+    impersonation_admin_username = ThreeScale.config.impersonation_admin[:username]
     assert_equal 'customer', classifier(email: 'user@example.com', username: 'user').user_type
 
     assert_equal '3scale', classifier(email: 'user@3scale.net', username: 'user').user_type
diff --git a/test/unit/three_scale/analytics/user_tracking_test.rb b/test/unit/three_scale/analytics/user_tracking_test.rb
index b5c2e289d7..7e8680fbe3 100644
--- a/test/unit/three_scale/analytics/user_tracking_test.rb
+++ b/test/unit/three_scale/analytics/user_tracking_test.rb
@@ -136,7 +136,7 @@ def setup
     end
 
     test 'do not track impersonation admins' do
-      @user.username = ThreeScale.config.impersonation_admin['username']
+      @user.username = ThreeScale.config.impersonation_admin[:username]
       refute UserTracking.new(@user).can_send?
     end
   end
diff --git a/test/unit/three_scale/sso_test.rb b/test/unit/three_scale/sso_test.rb
index e9ed9cd142..8761536119 100644
--- a/test/unit/three_scale/sso_test.rb
+++ b/test/unit/three_scale/sso_test.rb
@@ -20,7 +20,7 @@ class ThreeScale::SsoTest < ActiveSupport::TestCase
 
     decoder = ThreeScale::SSO::Encryptor.new ThreeScale::SSO.generate_sso_key
 
-    assert_raise ActiveSupport::MessageVerifier::InvalidSignature do
+    assert_raise ActiveSupport::MessageEncryptor::InvalidMessage do
       decoder.decrypt_token token
     end
   end
diff --git a/test/unit/user_test.rb b/test/unit/user_test.rb
index 2023ec570c..85c8ab4750 100644
--- a/test/unit/user_test.rb
+++ b/test/unit/user_test.rb
@@ -382,7 +382,7 @@ class ExistingProviderUserTest < ActiveSupport::TestCase
     test 'send lost password email on :generate_lost_password_token!' do
       @user.account.update_column(:provider, true) # rubocop:disable Rails/SkipsModelValidations
 
-      perform_enqueued_jobs(only: ActionMailer::DeliveryJob) do
+      perform_enqueued_jobs(only: ActionMailer::MailDeliveryJob) do
         @user.generate_lost_password_token!
       end
       message = ActionMailer::Base.deliveries.last
@@ -395,7 +395,7 @@ class ExistingProviderUserTest < ActiveSupport::TestCase
     test 'send buyer lost password email on :generate_lost_password_token!' do
       @user.account.update_column(:provider, false) # rubocop:disable Rails/SkipsModelValidations
 
-      perform_enqueued_jobs(only: ActionMailer::DeliveryJob) do
+      perform_enqueued_jobs(only: ActionMailer::MailDeliveryJob) do
         @user.generate_lost_password_token!
       end
 
diff --git a/test/workers/active_job_uniqueness_test.rb b/test/workers/active_job_uniqueness_test.rb
index 7ebdd936af..068718e781 100644
--- a/test/workers/active_job_uniqueness_test.rb
+++ b/test/workers/active_job_uniqueness_test.rb
@@ -37,8 +37,8 @@ class ActiveJobUniquenessTest < ActiveSupport::TestCase
       JobUniquenessTestWorker.perform_later
     end
     assert_enqueued_jobs 1, only: JobUniquenessTestWorker
-    # In Rails 6.0 we can just call #perform_enqueued_jobs
-    enqueued_jobs.each { |job_data| instantiate_job(job_data).perform_now }
+
+    perform_enqueued_jobs
 
     assert_equal 1, JobUniquenessTestWorker.run_counter
     assert_equal 1, locks