diff --git a/config/initializers/cookies_serializer.rb b/config/initializers/cookies_serializer.rb
deleted file mode 100644
index 5a6a32d37..000000000
--- a/config/initializers/cookies_serializer.rb
+++ /dev/null
@@ -1,5 +0,0 @@
-# Be sure to restart your server when you modify this file.
-
-# Specify a serializer for the signed and encrypted cookie jars.
-# Valid options are :json, :marshal, and :hybrid.
-Rails.application.config.action_dispatch.cookies_serializer = :json
diff --git a/config/initializers/new_framework_defaults_7_0.rb b/config/initializers/new_framework_defaults_7_0.rb
index cbd23a7ce..488587cfe 100644
--- a/config/initializers/new_framework_defaults_7_0.rb
+++ b/config/initializers/new_framework_defaults_7_0.rb
@@ -97,26 +97,9 @@ Rails.application.config.action_dispatch.default_headers = {
 # If you're upgrading and haven't set `cookies_serializer` previously, your cookie serializer
 # is `:marshal`. The default for new apps is `:json`.
 #
-# Rails.application.config.action_dispatch.cookies_serializer = :json
-#
-#
-# To migrate an existing application to the `:json` serializer, use the `:hybrid` option.
-#
-# Rails transparently deserializes existing (Marshal-serialized) cookies on read and
-# re-writes them in the JSON format.
-#
-# It is fine to use `:hybrid` long term; you should do that until you're confident *all* your cookies
-# have been converted to JSON. To keep using `:hybrid` long term, move this config to its own
-# initializer or to `config/application.rb`.
-#
-# Rails.application.config.action_dispatch.cookies_serializer = :hybrid
-#
-#
-# If your cookies can't yet be serialized to JSON, keep using `:marshal` for backward-compatibility.
-#
 # If you have configured the serializer elsewhere, you can remove this section of the file.
 #
-# See https://guides.rubyonrails.org/action_controller_overview.html#cookies for more information.
+Rails.application.config.action_dispatch.cookies_serializer = :json
 
 # Change the return value of `ActionDispatch::Request#content_type` to the Content-Type header without modification.
 # Rails.application.config.action_dispatch.return_only_request_media_type_on_content_type = false