- Chg #4071: `mail` component renamed to `mailer`, `yii\log\EmailTarget::$mail` renamed to `yii\log\EmailTarget::$mailer` (samdark)
- Chg #4147: `BaseMailer::compose()` will not overwrite the `message` parameter if it is explicitly provided (qiangxue)
- Chg #4201: change default value of `SyslogTarget::facility` from LOG_SYSLOG to LOG_USER (dizews)
- Chg #4211: BaseActiveRecord::populateRecord now silently hide selected columns that are not defined in AR instead of failing with an error (miramir)
- Chg #4227: `\yii\widgets\LinkPager::$hideOnSinglePage` is now `true` by default (samdark)
- Chg #4310: Removed `$data` from signature of `yii\rbac\ManagerInterface` (samdark)
- Chg #4310: Removed `$data` from signature of `yii\rbac\ManagerInterface` (samdark)
- Chg #4318: `yii\helpers\Html::ul()` and `ol()` will return an empty list tag if an empty item array is given (qiangxue)
- Chg #4331: `yii\helpers\Url` now uses `UrlManager` to determine base URL when generating URLs (qiangxue)
- Chg: Replaced `clearAll()` and `clearAllAssignments()` in `yii\rbac\ManagerInterface` with `removeAll()`, `removeAllRoles()`, `removeAllPermissions()`, `removeAllRules()` and `removeAllAssignments()` (qiangxue)