The MediaWiki team have announced the first stable release of the 1.16 series. This new version encompasses the following changes since 1.15.x:
By default, this new system makes a lot of database queries. If your database is particularly slow, or if your system administrator limits your query count, or if you want to squeeze as much performance as possible out of Mediawiki, set $wgCacheDirectory to a writable path on
the local filesystem. Make sure you have the DBA extension for PHP installed, this will improve performance further.
You can learn more or grab a copy from the MediaWiki website.