Thread:Project:Support desk/MW moving, what version?/reply (4)

MediaWiki 1.18 runs fine under PHP 5.3. If you run into problems, then maybe because of extensions, which you use. Trying to update them might help; if there is no version for 1.18, which runs under PHP 5.3, then maybe there is one for MediaWiki 1.20. However, PHP 5.3 has been around for quite some while already and I think it is rather unlikely that you run into major trouble.

And you need MySQL 5.0 at least.

All these information can also be found in one of the text files, which come with the MediaWiki package; I think they are in the file called RELEASE_NOTES or so.