diff --git a/config/initializers/new_framework_defaults_7_1.rb b/config/initializers/new_framework_defaults_7_1.rb
index b88647b52..473525c47 100644
--- a/config/initializers/new_framework_defaults_7_1.rb
+++ b/config/initializers/new_framework_defaults_7_1.rb
@@ -158,7 +158,7 @@ end
 # behavior would allow assignment but silently not persist changes to the
 # database.
 #++
-# Rails.application.config.active_record.raise_on_assign_to_attr_readonly = true
+Rails.application.config.active_record.raise_on_assign_to_attr_readonly = true
 
 ###
 # Enable validating only parent-related columns for presence when the parent is mandatory.