Transitioning from php3 to php4

Hi, I'm not sure if this is the proper forum for this question, if it is not, please let me know! I have several sites that need to be upgraded from php3 to php4. In order to test compliance of the php3 code on php4, I need to know exactly which functions have different usage / results on php4. I know that include() and rand() work differently, any others? Does anyone know of an article / page in docs that explains this? There was a page like this on php.net when php4 was first released, but I can't find it anymore. The faq on this does not have any useful info. Thanks, Chana Black