Thread:Project:Support desk/Wiki no longer working/reply (8)

Yes, it is! :-)

Take care with the PHP and MySQL versions, which are supported. If you don't want to have a broken system during update, you should upgrade to MediaWiki 1.18. Newer versions will only work, if you use a newer MySQL version - MySQL 5.0.2 at least.

After your host updated MySQL to at least 5.0.2 and PHP to 5.3.2 or newer, you can finally update to MediaWiki 1.21.