- Bug #5260: `yii\i18n\Formatter::decimalSeparator` and `yii\i18n\Formatter::thousandSeparator` where not configurable when intl is not installed (execut, cebe)
- Bug #5314: Fixed typo in the implementation of `yii\web\Session::getHasSessionId()` (qiangxue)
- Bug #5323: Nested dropdown does not work for `yii\bootstrap\DropDown` (aryraditya)
- Bug #5336: `yii\bootstrap\DropDown` should register bootstrap plugin asset (zelenin)
- Bug: Date and time formatting now assumes UTC as the timezone for input dates unless a timezone is explicitly given (cebe)
- Enh #4040: Added `$viewFile` and `$params` to the `EVENT_BEFORE_RENDER` and `EVENT_AFTER_RENDER` events for `View` (qiangxue)
- Enh #4275: Added `removeChildren()` to `yii\rbac\ManagerInterface` and implementations (samdark)