diff --git a/.circleci/config.yml b/.circleci/config.yml
index b4fd021f..18a69c08 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -24,662 +24,6 @@ common_pg_environment_vars: &common_pg_environment_vars
 version: 2
 jobs:
 
-  build_2.5.9_rails_5_2:
-    docker:
-      - image: ruby:2.5.9-alpine
-        <<: *common_ruby_environment
-      - image: postgres:9.6-alpine
-        environment:
-          PGDATA: /dev/shm/pgdata
-          <<: *common_pg_environment_vars
-      - image: redis:4-alpine
-    steps:
-      - checkout
-
-      - run:
-          name: Setup RAM disk
-          command: |
-            rm -rf ~/project/tmp ;
-            mkdir /dev/shm/tmp ;
-            ln -s /dev/shm/tmp ~/project/tmp
-
-      - run:
-          name: Setup requirements
-          command: |
-            apk add --update git bash build-base postgresql-dev sqlite-dev tzdata nodejs
-
-      - run:
-          name: Configure bundler
-          command: |
-            unset \
-              BUNDLE_APP_CONFIG \
-              GEM_HOME \
-              BUNDLE_PATH \
-              BUNDLE_BIN
-            bundle config --local gemfile $PWD/gemfiles/rails_5_2.gemfile
-
-      - restore_cache:
-          keys:
-            - v2-bundle-2.5.9-rails_5_2-{{ .Branch }}
-            - v2-bundle-2.5.9-rails_5_2
-            - v2-bundle-2.5.9
-
-      - run:
-          name: Install bundle
-          command: |
-            unset \
-              BUNDLE_APP_CONFIG \
-              GEM_HOME \
-              BUNDLE_PATH \
-              BUNDLE_BIN
-            bundle install --jobs=3 --retry=3 --path=$PWD/vendor/bundle
-
-      # The default Ruby containers modify the behaviour of Bundler in a way that breaks
-      # the CI since it makes it harder to run multiple apps in a single container
-      # See https://github.com/docker-library/docs/pull/1221/files for a summary
-      # Unsettting the variables restores the default behaviour
-      - run:
-          name: Run test suite
-          command: |
-            unset \
-              RACK_ENV \
-              RAILS_ENV \
-              BUNDLE_APP_CONFIG \
-              GEM_HOME \
-              BUNDLE_PATH \
-              BUNDLE_BIN
-            bundle exec rspec
-
-      - save_cache:
-          key: v2-bundle-2.5.9-rails_5_2-{{ .Branch }}
-          paths:
-            - ~/project/vendor/bundle
-            - ~/project/vendor/bundle-scaffold
-      - save_cache:
-          key: v2-bundle-2.5.9-rails_5_2
-          paths:
-            - ~/project/vendor/bundle
-            - ~/project/vendor/bundle-scaffold
-      - save_cache:
-          key: v2-bundle-2.5.9
-          paths:
-            - ~/project/vendor/bundle
-            - ~/project/vendor/bundle-scaffold
-
-  build_2.5.9_rails_6_0:
-    docker:
-      - image: ruby:2.5.9-alpine
-        <<: *common_ruby_environment
-      - image: postgres:9.6-alpine
-        environment:
-          PGDATA: /dev/shm/pgdata
-          <<: *common_pg_environment_vars
-      - image: redis:4-alpine
-    steps:
-      - checkout
-
-      - run:
-          name: Setup RAM disk
-          command: |
-            rm -rf ~/project/tmp ;
-            mkdir /dev/shm/tmp ;
-            ln -s /dev/shm/tmp ~/project/tmp
-
-      - run:
-          name: Setup requirements
-          command: |
-            apk add --update git bash build-base postgresql-dev sqlite-dev tzdata nodejs
-
-      - run:
-          name: Configure bundler
-          command: |
-            unset \
-              BUNDLE_APP_CONFIG \
-              GEM_HOME \
-              BUNDLE_PATH \
-              BUNDLE_BIN
-            bundle config --local gemfile $PWD/gemfiles/rails_6_0.gemfile
-
-      - restore_cache:
-          keys:
-            - v2-bundle-2.5.9-rails_6_0-{{ .Branch }}
-            - v2-bundle-2.5.9-rails_6_0
-            - v2-bundle-2.5.9
-
-      - run:
-          name: Install bundle
-          command: |
-            unset \
-              BUNDLE_APP_CONFIG \
-              GEM_HOME \
-              BUNDLE_PATH \
-              BUNDLE_BIN
-            bundle install --jobs=3 --retry=3 --path=$PWD/vendor/bundle
-
-      # The default Ruby containers modify the behaviour of Bundler in a way that breaks
-      # the CI since it makes it harder to run multiple apps in a single container
-      # See https://github.com/docker-library/docs/pull/1221/files for a summary
-      # Unsettting the variables restores the default behaviour
-      - run:
-          name: Run test suite
-          command: |
-            unset \
-              RACK_ENV \
-              RAILS_ENV \
-              BUNDLE_APP_CONFIG \
-              GEM_HOME \
-              BUNDLE_PATH \
-              BUNDLE_BIN
-            bundle exec rspec
-
-      - save_cache:
-          key: v2-bundle-2.5.9-rails_6_0-{{ .Branch }}
-          paths:
-            - ~/project/vendor/bundle
-            - ~/project/vendor/bundle-scaffold
-      - save_cache:
-          key: v2-bundle-2.5.9-rails_6_0
-          paths:
-            - ~/project/vendor/bundle
-            - ~/project/vendor/bundle-scaffold
-      - save_cache:
-          key: v2-bundle-2.5.9
-          paths:
-            - ~/project/vendor/bundle
-            - ~/project/vendor/bundle-scaffold
-
-  build_2.5.9_rails_6_1:
-    docker:
-      - image: ruby:2.5.9-alpine
-        <<: *common_ruby_environment
-      - image: postgres:9.6-alpine
-        environment:
-          PGDATA: /dev/shm/pgdata
-          <<: *common_pg_environment_vars
-      - image: redis:4-alpine
-    steps:
-      - checkout
-
-      - run:
-          name: Setup RAM disk
-          command: |
-            rm -rf ~/project/tmp ;
-            mkdir /dev/shm/tmp ;
-            ln -s /dev/shm/tmp ~/project/tmp
-
-      - run:
-          name: Setup requirements
-          command: |
-            apk add --update git bash build-base postgresql-dev sqlite-dev tzdata nodejs
-
-      - run:
-          name: Configure bundler
-          command: |
-            unset \
-              BUNDLE_APP_CONFIG \
-              GEM_HOME \
-              BUNDLE_PATH \
-              BUNDLE_BIN
-            bundle config --local gemfile $PWD/gemfiles/rails_6_1.gemfile
-
-      - restore_cache:
-          keys:
-            - v2-bundle-2.5.9-rails_6_1-{{ .Branch }}
-            - v2-bundle-2.5.9-rails_6_1
-            - v2-bundle-2.5.9
-
-      - run:
-          name: Install bundle
-          command: |
-            unset \
-              BUNDLE_APP_CONFIG \
-              GEM_HOME \
-              BUNDLE_PATH \
-              BUNDLE_BIN
-            bundle install --jobs=3 --retry=3 --path=$PWD/vendor/bundle
-
-      # The default Ruby containers modify the behaviour of Bundler in a way that breaks
-      # the CI since it makes it harder to run multiple apps in a single container
-      # See https://github.com/docker-library/docs/pull/1221/files for a summary
-      # Unsettting the variables restores the default behaviour
-      - run:
-          name: Run test suite
-          command: |
-            unset \
-              RACK_ENV \
-              RAILS_ENV \
-              BUNDLE_APP_CONFIG \
-              GEM_HOME \
-              BUNDLE_PATH \
-              BUNDLE_BIN
-            bundle exec rspec
-
-      - save_cache:
-          key: v2-bundle-2.5.9-rails_6_1-{{ .Branch }}
-          paths:
-            - ~/project/vendor/bundle
-            - ~/project/vendor/bundle-scaffold
-      - save_cache:
-          key: v2-bundle-2.5.9-rails_6_1
-          paths:
-            - ~/project/vendor/bundle
-            - ~/project/vendor/bundle-scaffold
-      - save_cache:
-          key: v2-bundle-2.5.9
-          paths:
-            - ~/project/vendor/bundle
-            - ~/project/vendor/bundle-scaffold
-
-  build_2.6.10_rails_5_2:
-    docker:
-      - image: ruby:2.6.10-alpine
-        <<: *common_ruby_environment
-      - image: postgres:9.6-alpine
-        environment:
-          PGDATA: /dev/shm/pgdata
-          <<: *common_pg_environment_vars
-      - image: redis:4-alpine
-    steps:
-      - checkout
-
-      - run:
-          name: Setup RAM disk
-          command: |
-            rm -rf ~/project/tmp ;
-            mkdir /dev/shm/tmp ;
-            ln -s /dev/shm/tmp ~/project/tmp
-
-      - run:
-          name: Setup requirements
-          command: |
-            apk add --update git bash build-base postgresql-dev sqlite-dev tzdata nodejs
-
-      - run:
-          name: Configure bundler
-          command: |
-            unset \
-              BUNDLE_APP_CONFIG \
-              GEM_HOME \
-              BUNDLE_PATH \
-              BUNDLE_BIN
-            bundle config --local gemfile $PWD/gemfiles/rails_5_2.gemfile
-
-      - restore_cache:
-          keys:
-            - v2-bundle-2.6.10-rails_5_2-{{ .Branch }}
-            - v2-bundle-2.6.10-rails_5_2
-            - v2-bundle-2.6.10
-
-      - run:
-          name: Install bundle
-          command: |
-            unset \
-              BUNDLE_APP_CONFIG \
-              GEM_HOME \
-              BUNDLE_PATH \
-              BUNDLE_BIN
-            bundle install --jobs=3 --retry=3 --path=$PWD/vendor/bundle
-
-      # The default Ruby containers modify the behaviour of Bundler in a way that breaks
-      # the CI since it makes it harder to run multiple apps in a single container
-      # See https://github.com/docker-library/docs/pull/1221/files for a summary
-      # Unsettting the variables restores the default behaviour
-      - run:
-          name: Run test suite
-          command: |
-            unset \
-              RACK_ENV \
-              RAILS_ENV \
-              BUNDLE_APP_CONFIG \
-              GEM_HOME \
-              BUNDLE_PATH \
-              BUNDLE_BIN
-            bundle exec rspec
-
-      - save_cache:
-          key: v2-bundle-2.6.10-rails_5_2-{{ .Branch }}
-          paths:
-            - ~/project/vendor/bundle
-            - ~/project/vendor/bundle-scaffold
-      - save_cache:
-          key: v2-bundle-2.6.10-rails_5_2
-          paths:
-            - ~/project/vendor/bundle
-            - ~/project/vendor/bundle-scaffold
-      - save_cache:
-          key: v2-bundle-2.6.10
-          paths:
-            - ~/project/vendor/bundle
-            - ~/project/vendor/bundle-scaffold
-
-  build_2.6.10_rails_6_0:
-    docker:
-      - image: ruby:2.6.10-alpine
-        <<: *common_ruby_environment
-      - image: postgres:9.6-alpine
-        environment:
-          PGDATA: /dev/shm/pgdata
-          <<: *common_pg_environment_vars
-      - image: redis:4-alpine
-    steps:
-      - checkout
-
-      - run:
-          name: Setup RAM disk
-          command: |
-            rm -rf ~/project/tmp ;
-            mkdir /dev/shm/tmp ;
-            ln -s /dev/shm/tmp ~/project/tmp
-
-      - run:
-          name: Setup requirements
-          command: |
-            apk add --update git bash build-base postgresql-dev sqlite-dev tzdata nodejs
-
-      - run:
-          name: Configure bundler
-          command: |
-            unset \
-              BUNDLE_APP_CONFIG \
-              GEM_HOME \
-              BUNDLE_PATH \
-              BUNDLE_BIN
-            bundle config --local gemfile $PWD/gemfiles/rails_6_0.gemfile
-
-      - restore_cache:
-          keys:
-            - v2-bundle-2.6.10-rails_6_0-{{ .Branch }}
-            - v2-bundle-2.6.10-rails_6_0
-            - v2-bundle-2.6.10
-
-      - run:
-          name: Install bundle
-          command: |
-            unset \
-              BUNDLE_APP_CONFIG \
-              GEM_HOME \
-              BUNDLE_PATH \
-              BUNDLE_BIN
-            bundle install --jobs=3 --retry=3 --path=$PWD/vendor/bundle
-
-      # The default Ruby containers modify the behaviour of Bundler in a way that breaks
-      # the CI since it makes it harder to run multiple apps in a single container
-      # See https://github.com/docker-library/docs/pull/1221/files for a summary
-      # Unsettting the variables restores the default behaviour
-      - run:
-          name: Run test suite
-          command: |
-            unset \
-              RACK_ENV \
-              RAILS_ENV \
-              BUNDLE_APP_CONFIG \
-              GEM_HOME \
-              BUNDLE_PATH \
-              BUNDLE_BIN
-            bundle exec rspec
-
-      - save_cache:
-          key: v2-bundle-2.6.10-rails_6_0-{{ .Branch }}
-          paths:
-            - ~/project/vendor/bundle
-            - ~/project/vendor/bundle-scaffold
-      - save_cache:
-          key: v2-bundle-2.6.10-rails_6_0
-          paths:
-            - ~/project/vendor/bundle
-            - ~/project/vendor/bundle-scaffold
-      - save_cache:
-          key: v2-bundle-2.6.10
-          paths:
-            - ~/project/vendor/bundle
-            - ~/project/vendor/bundle-scaffold
-
-  build_2.6.10_rails_6_1:
-    docker:
-      - image: ruby:2.6.10-alpine
-        <<: *common_ruby_environment
-      - image: postgres:9.6-alpine
-        environment:
-          PGDATA: /dev/shm/pgdata
-          <<: *common_pg_environment_vars
-      - image: redis:4-alpine
-    steps:
-      - checkout
-
-      - run:
-          name: Setup RAM disk
-          command: |
-            rm -rf ~/project/tmp ;
-            mkdir /dev/shm/tmp ;
-            ln -s /dev/shm/tmp ~/project/tmp
-
-      - run:
-          name: Setup requirements
-          command: |
-            apk add --update git bash build-base postgresql-dev sqlite-dev tzdata nodejs
-
-      - run:
-          name: Configure bundler
-          command: |
-            unset \
-              BUNDLE_APP_CONFIG \
-              GEM_HOME \
-              BUNDLE_PATH \
-              BUNDLE_BIN
-            bundle config --local gemfile $PWD/gemfiles/rails_6_1.gemfile
-
-      - restore_cache:
-          keys:
-            - v2-bundle-2.6.10-rails_6_1-{{ .Branch }}
-            - v2-bundle-2.6.10-rails_6_1
-            - v2-bundle-2.6.10
-
-      - run:
-          name: Install bundle
-          command: |
-            unset \
-              BUNDLE_APP_CONFIG \
-              GEM_HOME \
-              BUNDLE_PATH \
-              BUNDLE_BIN
-            bundle install --jobs=3 --retry=3 --path=$PWD/vendor/bundle
-
-      # The default Ruby containers modify the behaviour of Bundler in a way that breaks
-      # the CI since it makes it harder to run multiple apps in a single container
-      # See https://github.com/docker-library/docs/pull/1221/files for a summary
-      # Unsettting the variables restores the default behaviour
-      - run:
-          name: Run test suite
-          command: |
-            unset \
-              RACK_ENV \
-              RAILS_ENV \
-              BUNDLE_APP_CONFIG \
-              GEM_HOME \
-              BUNDLE_PATH \
-              BUNDLE_BIN
-            bundle exec rspec
-
-      - save_cache:
-          key: v2-bundle-2.6.10-rails_6_1-{{ .Branch }}
-          paths:
-            - ~/project/vendor/bundle
-            - ~/project/vendor/bundle-scaffold
-      - save_cache:
-          key: v2-bundle-2.6.10-rails_6_1
-          paths:
-            - ~/project/vendor/bundle
-            - ~/project/vendor/bundle-scaffold
-      - save_cache:
-          key: v2-bundle-2.6.10
-          paths:
-            - ~/project/vendor/bundle
-            - ~/project/vendor/bundle-scaffold
-
-  build_2.7.6_rails_6_0:
-    docker:
-      - image: ruby:2.7.6-alpine
-        <<: *common_ruby_environment
-      - image: postgres:9.6-alpine
-        environment:
-          PGDATA: /dev/shm/pgdata
-          <<: *common_pg_environment_vars
-      - image: redis:4-alpine
-    steps:
-      - checkout
-
-      - run:
-          name: Setup RAM disk
-          command: |
-            rm -rf ~/project/tmp ;
-            mkdir /dev/shm/tmp ;
-            ln -s /dev/shm/tmp ~/project/tmp
-
-      - run:
-          name: Setup requirements
-          command: |
-            apk add --update git bash build-base postgresql-dev sqlite-dev tzdata nodejs
-
-      - run:
-          name: Configure bundler
-          command: |
-            unset \
-              BUNDLE_APP_CONFIG \
-              GEM_HOME \
-              BUNDLE_PATH \
-              BUNDLE_BIN
-            bundle config --local gemfile $PWD/gemfiles/rails_6_0.gemfile
-
-      - restore_cache:
-          keys:
-            - v2-bundle-2.7.6-rails_6_0-{{ .Branch }}
-            - v2-bundle-2.7.6-rails_6_0
-            - v2-bundle-2.7.6
-
-      - run:
-          name: Install bundle
-          command: |
-            unset \
-              BUNDLE_APP_CONFIG \
-              GEM_HOME \
-              BUNDLE_PATH \
-              BUNDLE_BIN
-            bundle install --jobs=3 --retry=3 --path=$PWD/vendor/bundle
-
-      # The default Ruby containers modify the behaviour of Bundler in a way that breaks
-      # the CI since it makes it harder to run multiple apps in a single container
-      # See https://github.com/docker-library/docs/pull/1221/files for a summary
-      # Unsettting the variables restores the default behaviour
-      - run:
-          name: Run test suite
-          command: |
-            unset \
-              RACK_ENV \
-              RAILS_ENV \
-              BUNDLE_APP_CONFIG \
-              GEM_HOME \
-              BUNDLE_PATH \
-              BUNDLE_BIN
-            bundle exec rspec
-
-      - save_cache:
-          key: v2-bundle-2.7.6-rails_6_0-{{ .Branch }}
-          paths:
-            - ~/project/vendor/bundle
-            - ~/project/vendor/bundle-scaffold
-      - save_cache:
-          key: v2-bundle-2.7.6-rails_6_0
-          paths:
-            - ~/project/vendor/bundle
-            - ~/project/vendor/bundle-scaffold
-      - save_cache:
-          key: v2-bundle-2.7.6
-          paths:
-            - ~/project/vendor/bundle
-            - ~/project/vendor/bundle-scaffold
-
-  build_2.7.6_rails_6_1:
-    docker:
-      - image: ruby:2.7.6-alpine
-        <<: *common_ruby_environment
-      - image: postgres:9.6-alpine
-        environment:
-          PGDATA: /dev/shm/pgdata
-          <<: *common_pg_environment_vars
-      - image: redis:4-alpine
-    steps:
-      - checkout
-
-      - run:
-          name: Setup RAM disk
-          command: |
-            rm -rf ~/project/tmp ;
-            mkdir /dev/shm/tmp ;
-            ln -s /dev/shm/tmp ~/project/tmp
-
-      - run:
-          name: Setup requirements
-          command: |
-            apk add --update git bash build-base postgresql-dev sqlite-dev tzdata nodejs
-
-      - run:
-          name: Configure bundler
-          command: |
-            unset \
-              BUNDLE_APP_CONFIG \
-              GEM_HOME \
-              BUNDLE_PATH \
-              BUNDLE_BIN
-            bundle config --local gemfile $PWD/gemfiles/rails_6_1.gemfile
-
-      - restore_cache:
-          keys:
-            - v2-bundle-2.7.6-rails_6_1-{{ .Branch }}
-            - v2-bundle-2.7.6-rails_6_1
-            - v2-bundle-2.7.6
-
-      - run:
-          name: Install bundle
-          command: |
-            unset \
-              BUNDLE_APP_CONFIG \
-              GEM_HOME \
-              BUNDLE_PATH \
-              BUNDLE_BIN
-            bundle install --jobs=3 --retry=3 --path=$PWD/vendor/bundle
-
-      # The default Ruby containers modify the behaviour of Bundler in a way that breaks
-      # the CI since it makes it harder to run multiple apps in a single container
-      # See https://github.com/docker-library/docs/pull/1221/files for a summary
-      # Unsettting the variables restores the default behaviour
-      - run:
-          name: Run test suite
-          command: |
-            unset \
-              RACK_ENV \
-              RAILS_ENV \
-              BUNDLE_APP_CONFIG \
-              GEM_HOME \
-              BUNDLE_PATH \
-              BUNDLE_BIN
-            bundle exec rspec
-
-      - save_cache:
-          key: v2-bundle-2.7.6-rails_6_1-{{ .Branch }}
-          paths:
-            - ~/project/vendor/bundle
-            - ~/project/vendor/bundle-scaffold
-      - save_cache:
-          key: v2-bundle-2.7.6-rails_6_1
-          paths:
-            - ~/project/vendor/bundle
-            - ~/project/vendor/bundle-scaffold
-      - save_cache:
-          key: v2-bundle-2.7.6
-          paths:
-            - ~/project/vendor/bundle
-            - ~/project/vendor/bundle-scaffold
-
   build_3.0.4_rails_6_0:
     docker:
       - image: ruby:3.0.4-alpine
@@ -728,6 +72,7 @@ jobs:
               GEM_HOME \
               BUNDLE_PATH \
               BUNDLE_BIN
+            gem update --system
             bundle install --jobs=3 --retry=3 --path=$PWD/vendor/bundle
 
       # The default Ruby containers modify the behaviour of Bundler in a way that breaks
@@ -810,6 +155,7 @@ jobs:
               GEM_HOME \
               BUNDLE_PATH \
               BUNDLE_BIN
+            gem update --system
             bundle install --jobs=3 --retry=3 --path=$PWD/vendor/bundle
 
       # The default Ruby containers modify the behaviour of Bundler in a way that breaks
@@ -892,6 +238,7 @@ jobs:
               GEM_HOME \
               BUNDLE_PATH \
               BUNDLE_BIN
+            gem update --system
             bundle install --jobs=3 --retry=3 --path=$PWD/vendor/bundle
 
       # The default Ruby containers modify the behaviour of Bundler in a way that breaks
@@ -974,6 +321,7 @@ jobs:
               GEM_HOME \
               BUNDLE_PATH \
               BUNDLE_BIN
+            gem update --system
             bundle install --jobs=3 --retry=3 --path=$PWD/vendor/bundle
 
       # The default Ruby containers modify the behaviour of Bundler in a way that breaks
@@ -1013,27 +361,12 @@ workflows:
   version: 2
   test:
     jobs:
-
-      - build_2.5.9_rails_5_2
-
-      - build_2.5.9_rails_6_0
-
-      - build_2.5.9_rails_6_1
-
-      - build_2.6.10_rails_5_2
-
-      - build_2.6.10_rails_6_0
-
-      - build_2.6.10_rails_6_1
-
-      - build_2.7.6_rails_6_0
-
-      - build_2.7.6_rails_6_1
-
+    
       - build_3.0.4_rails_6_0
-
+    
       - build_3.0.4_rails_6_1
-
+    
       - build_3.1.2_rails_6_1
-
+    
       - build_3.1.2_rails_7_0
+    
diff --git a/.circleci/config.yml.erb b/.circleci/config.yml.erb
index 889dc3c0..01685f5b 100644
--- a/.circleci/config.yml.erb
+++ b/.circleci/config.yml.erb
@@ -22,17 +22,6 @@ common_pg_environment_vars: &common_pg_environment_vars
     POSTGRES_HOST_AUTH_METHOD: "trust"
 <%
   builds = [
-    ['2.5.9', 'rails_5_2'],
-    ['2.5.9', 'rails_6_0'],
-    ['2.5.9', 'rails_6_1'],
-
-    ['2.6.10', 'rails_5_2'],
-    ['2.6.10', 'rails_6_0'],
-    ['2.6.10', 'rails_6_1'],
-
-    ['2.7.6', 'rails_6_0'],
-    ['2.7.6', 'rails_6_1'],
-
     ['3.0.4', 'rails_6_0'],
     ['3.0.4', 'rails_6_1'],
 
@@ -91,6 +80,7 @@ jobs:
               GEM_HOME \
               BUNDLE_PATH \
               BUNDLE_BIN
+            gem update --system
             bundle install --jobs=3 --retry=3 --path=$PWD/vendor/bundle
 
       # The default Ruby containers modify the behaviour of Bundler in a way that breaks