CHANGELOG.md

*   Remove deprecated `Validatior#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](https://github.com/rails/rails/blob/4-1-stable/activemodel/CHANGELOG.md) for previous changes.