Blizzard has shared Wrath Classic Hotfixes, which includes updates to the Battle for Undercity quest chain, additional fixes to Bind on Blizzard Account items, and Engineering Auction House in Dalaran.
Wrath of the Lich King Classic
Zidormi will now reliably allow players to enter or leave the Battle for The Undercity. If you have haven’t started the Battle for The Undercity questlines, you must complete the following quests to enter: