Hello,
bugzilla.wikimedia.org is scheduled to be upgraded to version 4.0 on April 1st at 17:00GMT. This should not take much time and we will try to keep downtime to a minimum.
For the new features available in this release see: http://www.bugzilla.org/releases/4.0/release-notes.html#v40_feat
If you see any problems after the upgrade, please report them using https://bugzilla.wikimedia.org/enter_bug.cgi?product=Wikimedia and use the component Bugzilla.
Thanks -p