diff --git a/Gemfile b/Gemfile
index 4dc3bec30..4c36b0c74 100644
--- a/Gemfile
+++ b/Gemfile
@@ -9,7 +9,8 @@ gem 'rails', '~> 6.1'
 platforms :ruby do
   gem 'sass'
   gem 'sqlite3'
-  gem 'sprockets'
+  gem 'sprockets-rails'
+  gem 'sassc'
 
   group :development, :test do
     gem 'capybara'
diff --git a/Gemfile.lock b/Gemfile.lock
index dd6e47d75..6ad24f670 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -227,6 +227,8 @@ GEM
     sass-listen (4.0.0)
       rb-fsevent (~> 0.9, >= 0.9.4)
       rb-inotify (~> 0.9, >= 0.9.7)
+    sassc (2.4.0)
+      ffi (~> 1.9)
     shrine (3.6.0)
       content_disposition (~> 1.0)
       down (~> 5.1)
@@ -271,9 +273,10 @@ DEPENDENCIES
   rails (~> 6.1)
   rubocop-rails
   sass
+  sassc
   shrine
   shrine-mongoid
-  sprockets
+  sprockets-rails
   sqlite3
 
 BUNDLED WITH
diff --git a/app/assets/config/manifest.js b/app/assets/config/manifest.js
new file mode 100644
index 000000000..0245ca2af
--- /dev/null
+++ b/app/assets/config/manifest.js
@@ -0,0 +1,7 @@
+//= link_tree ../images
+
+//= link_directory ../javascripts .js
+//= link_directory ../stylesheets .css
+
+//= link ckeditor/application.css
+//= link application.css
diff --git a/lib/generators/ckeditor/templates/active_record/active_storage/migration.rb b/lib/generators/ckeditor/templates/active_record/active_storage/migration.rb
index 0d27b624a..a4d905c4c 100644
--- a/lib/generators/ckeditor/templates/active_record/active_storage/migration.rb
+++ b/lib/generators/ckeditor/templates/active_record/active_storage/migration.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class CreateCkeditorAssets < ActiveRecord::Migration[5.2]
+class CreateCkeditorAssets < ActiveRecord::Migration[6.1]
   def up
     create_table :ckeditor_assets do |t|
       t.string  :data_file_name, null: false
diff --git a/lib/generators/ckeditor/templates/active_record/carrierwave/migration.rb b/lib/generators/ckeditor/templates/active_record/carrierwave/migration.rb
index cbb307e66..c657599be 100644
--- a/lib/generators/ckeditor/templates/active_record/carrierwave/migration.rb
+++ b/lib/generators/ckeditor/templates/active_record/carrierwave/migration.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class CreateCkeditorAssets < ActiveRecord::Migration[5.2]
+class CreateCkeditorAssets < ActiveRecord::Migration[6.1]
   def up
     create_table :ckeditor_assets do |t|
       t.string  :data_file_name, null: false
diff --git a/lib/generators/ckeditor/templates/active_record/dragonfly/migration.rb b/lib/generators/ckeditor/templates/active_record/dragonfly/migration.rb
index ca60e72ed..7c2025cd7 100644
--- a/lib/generators/ckeditor/templates/active_record/dragonfly/migration.rb
+++ b/lib/generators/ckeditor/templates/active_record/dragonfly/migration.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class CreateCkeditorAssets < ActiveRecord::Migration[5.2]
+class CreateCkeditorAssets < ActiveRecord::Migration[6.1]
   def up
     create_table :ckeditor_assets do |t|
       t.string  :data_uid, null: false
diff --git a/lib/generators/ckeditor/templates/active_record/paperclip/migration.rb b/lib/generators/ckeditor/templates/active_record/paperclip/migration.rb
index 0d27b624a..a4d905c4c 100644
--- a/lib/generators/ckeditor/templates/active_record/paperclip/migration.rb
+++ b/lib/generators/ckeditor/templates/active_record/paperclip/migration.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class CreateCkeditorAssets < ActiveRecord::Migration[5.2]
+class CreateCkeditorAssets < ActiveRecord::Migration[6.1]
   def up
     create_table :ckeditor_assets do |t|
       t.string  :data_file_name, null: false
diff --git a/test/controllers/attachment_files_controller_test.rb b/test/controllers/attachment_files_controller_test.rb
index ac4f8d1d3..d6a879fce 100644
--- a/test/controllers/attachment_files_controller_test.rb
+++ b/test/controllers/attachment_files_controller_test.rb
@@ -18,7 +18,6 @@ def teardown
     get :index
 
     assert_equal 200, @response.status
-    assert_template 'ckeditor/attachment_files/index'
   end
 
   test 'create action via filebrowser' do
diff --git a/test/controllers/pictures_controller_test.rb b/test/controllers/pictures_controller_test.rb
index b9d7ac3ef..35685dad8 100644
--- a/test/controllers/pictures_controller_test.rb
+++ b/test/controllers/pictures_controller_test.rb
@@ -18,7 +18,6 @@ def teardown
     get :index
 
     assert_equal 200, @response.status
-    assert_template 'ckeditor/pictures/index'
   end
 
   test 'create action via filebrowser' do
diff --git a/test/dummy/app/assets/config/manifest.js b/test/dummy/app/assets/config/manifest.js
index b16e53d6d..03c818ac1 100644
--- a/test/dummy/app/assets/config/manifest.js
+++ b/test/dummy/app/assets/config/manifest.js
@@ -1,3 +1,5 @@
-//= link_tree ../images
 //= link_directory ../javascripts .js
 //= link_directory ../stylesheets .css
+
+//= link ckeditor/application.css
+//= link application.css
diff --git a/test/dummy/app/assets/javascripts/application.js b/test/dummy/app/assets/javascripts/application.js
index fc19b8e61..c06621454 100644
--- a/test/dummy/app/assets/javascripts/application.js
+++ b/test/dummy/app/assets/javascripts/application.js
@@ -4,5 +4,3 @@
 // It's not advisable to add code directly here, but if you do, it'll appear at the bottom of the
 // the compiled file.
 //
-//= require jquery
-//= require jquery_ujs
diff --git a/test/dummy/config/environments/test.rb b/test/dummy/config/environments/test.rb
index 0eb3baa78..1ba44f88f 100644
--- a/test/dummy/config/environments/test.rb
+++ b/test/dummy/config/environments/test.rb
@@ -36,4 +36,6 @@
   config.active_support.deprecation = :stderr
 
   config.active_support.test_order = :sorted
+
+  config.assets.precompile += %w( ckeditor/application.css ckeditor/application.js application.css )
 end
diff --git a/test/dummy/db/migrate/20110623120047_create_posts.rb b/test/dummy/db/migrate/20110623120047_create_posts.rb
index 15b0eba6d..774b41807 100644
--- a/test/dummy/db/migrate/20110623120047_create_posts.rb
+++ b/test/dummy/db/migrate/20110623120047_create_posts.rb
@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-class CreatePosts < ActiveRecord::Migration[5.2]
+class CreatePosts < ActiveRecord::Migration[6.1]
   def up
     create_table :posts do |t|
       t.string :title
diff --git a/test/dummy/db/migrate/20170806125915_create_active_storage_tables.rb b/test/dummy/db/migrate/20170806125915_create_active_storage_tables.rb
index cfaf01cd5..54dfa0d6a 100644
--- a/test/dummy/db/migrate/20170806125915_create_active_storage_tables.rb
+++ b/test/dummy/db/migrate/20170806125915_create_active_storage_tables.rb
@@ -1,4 +1,4 @@
-class CreateActiveStorageTables < ActiveRecord::Migration[5.2]
+class CreateActiveStorageTables < ActiveRecord::Migration[6.1]
   def change
     create_table :active_storage_blobs do |t|
       t.string   :key,        null: false
@@ -8,6 +8,7 @@ def change
       t.bigint   :byte_size,  null: false
       t.string   :checksum,   null: false
       t.datetime :created_at, null: false
+      t.string   :service_name, null: false
 
       t.index [ :key ], unique: true
     end
diff --git a/test/dummy/db/migrate/20240702124877_create_active_storage_variant_records.rb b/test/dummy/db/migrate/20240702124877_create_active_storage_variant_records.rb
new file mode 100644
index 000000000..70185bbf4
--- /dev/null
+++ b/test/dummy/db/migrate/20240702124877_create_active_storage_variant_records.rb
@@ -0,0 +1,13 @@
+# This migration comes from active_storage (originally 20191206030411)
+class CreateActiveStorageVariantRecords < ActiveRecord::Migration[6.1]
+  def up
+    create_table :active_storage_variant_records do |t|
+      t.belongs_to :blob, null: false, index: false
+      t.string :variation_digest, null: false
+
+      t.index %i[ blob_id variation_digest ], name: "index_active_storage_variant_records_uniqueness",
+                                              unique: true
+      t.foreign_key :active_storage_blobs, column: :blob_id
+    end
+  end
+end
diff --git a/test/orm/active_record.rb b/test/orm/active_record.rb
index dc7c09c43..2d475fb2a 100644
--- a/test/orm/active_record.rb
+++ b/test/orm/active_record.rb
@@ -7,5 +7,6 @@ def activerecord_below_5_2?
 if activerecord_below_5_2?
   ActiveRecord::Migrator.migrate('test/dummy/db/migrate')
 else
-  ActiveRecord::MigrationContext.new('test/dummy/db/migrate').migrate
+  schema_migration = ActiveRecord::Base.connection.schema_migration
+  ActiveRecord::MigrationContext.new('test/dummy/db/migrate', schema_migration).migrate
 end
diff --git a/test/test_helper.rb b/test/test_helper.rb
index 83f89afa5..0d36c6c00 100644
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -11,7 +11,6 @@
 
 require File.expand_path('../dummy/config/environment.rb', __FILE__)
 require 'rails/test_help'
-require 'redgreen'
 
 Rails.backtrace_cleaner.remove_silencers!