rails/activemodel/CHANGELOG.md

• Added undo_changes method to ActiveModel::Dirty API to restore all the changed values to the previous data.

  Igor G.

• Allow proc and symbol as values for only_integer of NumericalityValidator

  Robin Mehner

• has_secure_password now verifies that the given password is less than 72 characters if validations are enabled.

  Fixes #14591.

  Akshay Vishnoi

• Remove deprecated Validator#setup without replacement.

  See #10716.

  Kuldeep Aggarwal

• Add plural and singular form for length validator's default messages.

  Abd ar-Rahman Hamid

• Introduce validate as an alias for valid?.

  This is more intuitive when you want to run validations but don't care about the return value.

  Henrik Nyh

Please check 4-1-stable for previous changes.