Bugs in php 4.2.3.?

Hi, i recently had a problem with a script on a server, which uses php 4.2.3. I couldn't find the problem and so installed it on a different server and it worked right away. Only difference on that server was: php 4.2.2. I checked some sites and it seems there are some issues with postnuke, xoops and several other scripts with php 4.2.3. Is this a known bug, or is it s.th. like the register_globals thing, where you either need to update the script or set it to "On" in php.ini? Regards, Hendrik