added UPGRADE and CHANGELOG

framework/CHANGELOG.md

@@ -19,6 +19,7 @@ Yii Framework 2 Change Log
 - Enh #12592: Optimized `yii\filters\AccessController` on processing accessrules (dynasource)
 - Enh #12938: Allow to pass additional parameters to `yii\base\View::renderDynamic()` (mikehaertl)
 - Enh #13006: Added a `/` to the `yii\captcha\Captcha::$captchaAction` string to work correctly in a module also (boehsermoe)
+- Enh #15410: Added serialization abstraction layer under `yii\serialize\*` namespace (klimov-paul)
 - Removed methods marked as deprecated in 2.0.x (samdark)
 - Chg #14784: Signature of `yii\web\RequestParserInterface::parse()` changed to accept `yii\web\Request` instance as a sole argument (klimov-paul)
 - Chg #10771: Consistent behavior of `run()` method in all framework widgets. All return the result now for better extensibility (pkirill99, cebe)

framework/UPGRADE.md

@@ -106,6 +106,9 @@ Upgrade from Yii 2.0.x
   be configured there. Creating your own cache implementation you should implement `\Psr\SimpleCache\CacheInterface` or
   extend `yii\caching\SimpleCache` abstract class. Use `yii\caching\CacheInterface` only if you wish to replace `yii\caching\Cache`
   component providing your own solution for cache dependency handling.
+* `yii\caching\SimpleCache::$serializer` now should be `yii\serialize\SerializerInterface` instance or its DI compatible configuration.
+  Thus it does not longer accept pair of serialize/unserialize functions as an array. Use `yii\serialize\CallbackSerializer` or
+  other predefined serializer class from `yii\serialize\*` namespace instead.
 * Console command used to clear cache now calls related actions "clear" instead of "flush".
 * Yii autoloader was removed in favor of Composer-generated one. You should remove explicit inclusion of `Yii.php` from
   your entry `index.php` scripts. In case you have relied on class map, use `composer.json` instead of configuring it