Parts of players on US Server encountered Error_3007 after Patch 1.0.6a. The technicians in Blizzard investigated the problem and said that it caused by parts of telecommunication venders’ DNS adjustment.
Community Manager Lylirra expressed that, Blizzard was still paying attention to the problem, and reaffirmed that the maintenance on December 12th was mainly based on Database, that’s why the maintenance cost about 10 hours long time.
We posted the patch notes for 1.0.6a the Monday before we patched in the forums as a sticky, and on the day of the patch here. The only thing 1.0.6a included was a bug fix for an issue that could not be hotfixed (but was critical enough to address now rather than waiting for our next full patch cycle). Please note that the downtime experienced on Tuesday occurred across all Blizzards games, not just Diablo III. This is because the downtime was due to database maintenance, and not the deployment of the patch.