Upgrading jQuery from 1.3.2 and 1.4.2 to 1.5.1

Question

In my project we have made many applications which consist of jQuery 1.3.2 and 1.4.2 code. Now we are planning to upgrade to jQuery 1.5.1. Can anyone tell whether 1.5.1 or its previous versions are backwards compatible with 1.3.2 and 1.4.2? It would also be great if anyone could point me to some discrete source (links). I have tried a lot while googling but found nothing much, just that 1.5.1 supports IE9.

Answer 1

The API's for the main parts of Jquery haven't changed its mostly back end stuff and newer features that have been added.

see release notes for 1.5.1