Wikipedia has been upgraded to a new version of the MediaWiki software after the release of a beta for MediaWiki 1.5 last week, which necessitated nearly a day of editing downtime.

On Sunday, Chief Technical Officer Brion Vibber announced the release of MediaWiki 1.5beta1, which should have essentially the full range of features that will be in the 1.5 series. As is usual for MediaWiki software development, the sites of the Wikimedia Foundation serve as the base for beta testing.

The upgrade cycle began with some of the Foundation's miscellaneous wikis and then moved on to the major projects, beginning with Wikinews. The Wikimedia Commons site experienced some bugs as a result, but these were quickly repaired.

The process on the English Wikipedia began early on Monday, 27 June (at 05:38 UTC), at which point editing was disabled during the upgrade. This lasted for 21 hours and 20 minutes, with service resuming at 02:58 UTC on Tuesday, 28 June. However, some issues still had to be sorted out and reliable editing took another half hour to restore.

Vibber said that by completing the upgrade in less than 24 hours, the process had taken less time than he feared might be necessary. Since the English Wikipedia has the largest database, the others should not take as long unless problems arise. He indicated that "the remaining wikis will get upgraded bit by bit over the coming days."

New features

The biggest change involved in the upgrade is a revised schema for the database, which is the reason that an extended read-only period was necessary. This change should significantly speed up rename and delete operations on pages with long edit histories. It will also create a fixed ID for the most recent revision of a page, which will allow permanent links to current as well as old revisions of an article.

Another major new feature affects page moves, which will now be recorded in the log pages and appear separately in revision histories. These changes are expected to help in dealing with page-move vandalism, and a 'rollback' function for page moves will be available to administrators. Other changes include the availability of a 'diff' for edit previews, and the ability to specify a file name for uploads distinct from the original filename on the user's hard drive.