This is a summary of recent technology and site configuration changes that affect the English Wikipedia. Some bug fixes or new features described below have not yet gone live as of press time; the English Wikipedia is currently running version 1.26wmf3 (97fb5c0), and changes to the software with a version number higher than that will not yet be active. Configuration changes and changes to interface messages, however, become active immediately.
Revisions that show a 2004 page move from Wikipedia:Main Page to Wikipedia:Community Portal are now accessible. They were previously listed under an invalid title due to page move vandalism. Although they could be found through deleted contributions, they could not be undeleted or moved without the help of a system administrator. (bug 13729)
On December 10, Wikipedia database servers were upgraded to run MySQL version 5.1 from version 4.0. 
The master database server for English Wikipedia went down on Saturday, December 12 around 21:30 UTC, causing an outage that lasted for approximately 15 minutes before server admins resolved the problem.
There is a bug in php 5.3.1 with the __call() function, which causes a breakage in MediaWiki. This means that MediaWiki does not support php 5.3.1 at this time.