My php error log is getting full of "deprecated" errors on different lines of xmlrpc.inc and xmlrpcs.inc

This happens when the PHP in usage is version 5, and the error reporting level is set to include E_STRICT errors. Since the main development platform of the library remains (for the time being) PHP 4, there are no plans to fix this asap. The best workaround is to set the error reporting level to E_ALL ^ E_STRICT.