Face the Lich King Himself When Icecrown Citadel Comes to Wrath of the Lich King Classic October 12th

mmorpg.com:

World of Warcraft Classic will open up Icecrown Citadel on October 12th as Wrath of the Lich King Classic continues getting new updates. Get ready to face the Lich King himself if you can get through the massive citadel and other bosses first.

The week of October 10th, Patch 3.4.3 will bring a  bunch of new content to Wrath of the Lich King Classic . Expect the arrival of three new dungeons–The Forge of Souls, Pit of Saron, and Halls of Reflection–as well as the introduction of the Random Dungeon Finder. Yes, Classic will be opening up the dungeon finder for easier group assembly. This should enhance the experience, especially if you play during off hours for your server or region.

WoTLK Classic also getsa new Titan Rune Dungeon — Defense Protocol Gamma, with fresh challenges and loot. The update also adds a brand new collections UI and more content to come. There’s a lot more detail in the PTR patch notes for the update.

Icecrown Citadel will open up on October 12th at 3:00 p.m. PDT globally, this is 10:00 p.m. GMT for those who need to track local times. There are five wings and 12 encounters to take on and you can do so in Normal or Heroic. If you haven't run this instance in a while, it should be an exciting challenge to make your way through and claim victory over boss after boss while also uncovering the mysteries in the citadel. And, of course, take on the Lich King.

Death Knights, Paladins, and Warriors can also take on the Shadowmourne quest chain to obtain the legendary axe when the update goes live. 

You can find out much more about the update, including newer adjustments over in the PTR notes. More on the official release will be on the way. See the announcement here at World of Warcraft.