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 1.25wmf12 (d1c5789), 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.
Seven bots / bot tasks were approved in the past week:
JCbot – To add portal boxes to article and category pages.
MGA73bot – To help migrate GFDL images, and move some images to Commons.
A backwards compatibility fix has been implemented for file uploading on MediaWiki, allowing uploading tools including Commonist to work once again and resolving other uploading bugs that occurred with the September 16 code update on Wikimedia projects. 
The LocalisationUpdate extension had bugs that cause very high CPU usage, making it not suitable for deployment. The initial update.php run involved very heavy database queries, slowing down replication. Then, the code that checked for the last update.php run was using stale data from the slave servers. The extension has been modified to instead use a file-based storage system, and the extension is being tested before being deployed on Wikimedia sites. (bug 20774)
The file history page has been updated to show the thumbnail column only if the file type is an image. (r56917, bug 17747)
A new permission (sendemail) has been added to MediaWiki. This is set as enabled by default, but could be used to deal with spam problems. (r56962)
Chief developer Brion Vibber has announced he is leaving his position with the Wikimedia Foundation, and will be taking a new position as chief developer of StatusNet. (See "News and notes")