- 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 #4227: `\yii\widgets\LinkPager::$hideOnSinglePage` is now `true` by default (samdark)
- Chg: Replaced `clearAll()` and `clearAllAssignments()` in `yii\rbac\ManagerInterface` with `removeAll()`, `removeAllRoles()`, `removeAllPermissions()`, `removeAllRules()` and `removeAllAssignments()` (qiangxue)
- Chg: Added `$user` as the first parameter of `yii\rbac\Rule::execute()` (qiangxue)
- Chg: `yii\grid\DataColumn::getDataCellValue()` visibility is now `public` to allow accessing the value from a GridView directly (cebe)