- Removed `FileLoader` and used `\Twig_Loader_Filesystem` instead.
- Added support of Yii's aliases.
- Added `set()` that allows setting object properties.

Conflicts:
	framework/CHANGELOG.md

Refactored ActiveQuery::one() to be consistent with all() creation

Added tests that are making sure Gii isn't failing with errors

- Enh #4520: yii\caching/MemCache.php add sasl support (xjflyttp)

Fix signature validation

Updated guide

Refactored

as it is in RC phase now we should be able to report bugs if they occur.

Fix Russian translation

Fixes #4497: Bad Request, Unable to verify your data submission

Update intro-upgrade-from-v1.md

Fixes #4519: `yii\base\Model::isAttributeRequired()` should check if the `when` option of the validator is set