Here is a partial diff report regarding the component and config (attributes) changes between v4.0.7 and v4.1.0-beta2.
We generate these reports when developing the Ext4Yii framework. I would like to share it for anyone interested.
The report contains the:
 Deleted / renamed classes
 New classes
 New and deleted attributes (configs) for each class
 Existing attributes with their data type changed.
Have fun coding.