Mootools have now released the Core Version 1.2.5. This is the final version of the mootools 1.2 series.
Here is the change log.
- Fix for the fireEvent under IE9 beta.
- Forcing MooTools bind implementation to work with latest gecko/ webkit beta browsers.
- Fixes HTML Elements creation in IE9 Beta.
- Fixed Element garbage collection in IE.
Or, if you prefer, you can have look at the actual Code Diff.
But do not forget that there will be release of MooTool 1.3 in following days.
Source : MooTools Blog