[kh99]

I don't know exactly which php versions are recommended for each version of vbulletin - that information is probably on vbulletin.com somewhere. But I do know that using vb3 on a recent php version is likely to give you a lot of "this feature deprecated" messages, but you can turn them off. What I do is a search and replace on all the vb php files to replace:

error_reporting(E_ALL & ~E_NOTICE);

with

error_reporting(E_ALL & ~E_NOTICE & ~8192);

I've seen other people suggest that you can just put that second line in global.php (and in admincp and modcp global.php), but I've never actually tried it myself.