yii 1.1.x backward compatiblity

does yii 1.1.x have a backward compatibility especially with 1.0.9?

Check http://code.google.com/p/yii/source/browse/trunk/UPGRADE

can anybody give me a direct answer please?

There is no direct answer… as you didn’t ask a specific question… but is safe to assume that it’s not compatible with the code written for Yii 1.0.9

Y!! has posted there a link to the file where you can see what has changed in every version after the 1.0.9 to the latest release…