Blizzard has added Ahead of the Curve and Cutting Edge achievements for Ulduar in Wrath Classic.
Ahead of the Curve requires players to kill Yogg-Saron on 10/25 player pre-nerf difficulty before the next raid tier releases. To earn the Cutting Edge achievement, you’ll need to complete every hard-mode in Ulduar on 10/25 player pre-nerf difficulty before the next raid tier releases.
Ahead of the Curve: Yogg Saron – Defeat Yogg-Saron in Ulduar on 10 or 25-Player Pre-Nerf difficulty, before the release of the next raid tier.
Cutting Edge: Ulduar – Defeat every hard-mode boss in Ulduar on 10 or 25-Player Pre-Nerf difficulty, before the release of the next raid tier.