WoWDB

Ulduar: Halls of Lightning makes its return to current content via the Timewalking system introduced with Patch 6.2.  All players level 81 and above will be able to queue for the Timewalking version using the LFD tool when the special event is active.  The official highlights blog is here.  Don't forget to pick up A Frozen Path Through Time.

Some notes:

• Be careful to pull Bjarngrim when he is not in range of aggroing a trash pack with him.  If attempting  Lightning Struck, wait for Bjarngrim to gain  Temporary Electrical Charge before pulling him.
• The trash in the room below Volkhan will respawn as long as that boss is alive.  Try to pull as few mobs as possible and keep moving while doing AoE dps.  Hardest on heals due to  Melt Armor.
• Volkhan is straightforward.   Shatter Resistant is a DPS check, and earning it should not be difficult.
• Ionar's mechanic is that it dissipates into lightning balls that slowly chase the players.  Just don't trap yourself in a corner.
• Run out of melee range of Loken's  Lightning Nova - unless attempting  Timely Death, in which case everyone stacks on the tank for AoE healing while continuing to DPS.  Personal CDs are helpful.