Rails 5.0 Rails 5.1+ changed? → saved_change_to? _was → _before_last_save changed? → saved_changes? changed_attributes → saved_changes.transform_values(&:first)
Model callbacks behavior After Rails 4.x release, some changes were made on callbacks to split update on the model before and after writing data to the database. We had to be careful to use the correct helpers: _changed? for after_save callbacks, and previous_changes[:] for after_commit callbacks: