Any reason #in_batches is not backported to Rails 4.x?

Hello

The `ActiveRecord::Relation#in_batches`, similar to
`ActiveRecord::Relation#find_in_batches`, but which yields a collection
ofActiveRecord::Relation objects has been merged into master via
https://github.com/rails/rails/pull/20933. If I'm not mistaken, this is
not backported to older Rails versions—I've checked out the v4.2.5.rc2
tag, but couldn't find the method.

Is there a reason why this is not backported to older Rails versions?

New features are not backported to stable branches. See our maintenance policy http://guides.rubyonrails.org/maintenance_policy.html#new-features