Patch 2.1.0 was the first major patch after the release of Diablo III: Reaper of Souls and its associated patch 2.0.1. It introduced Seasons, Greater Rifts, and Leaderboards, all of which remain important endgame features.
The patch rebalanced game mechanics in several areas. The influence on healing from skills and items was increased, and that of Health Globes was reduced. All classes received numerous skill changes; improving Elemental Damage options was a common thread. All Two-handed weapons received a large damage increase.
Significant items added include Ramaladni's Gift, the first Legendary Gems, Roland's Legacy, and Hellfire Amulets. Numerous other Legendary Items were added, and many pre-existing Legendaries received new versions with unique powers for the first time.
Other notable changes included improved combat pet mechanics, reduced requirements for a number of Achievements, and mass-salvage buttons.