Season 13 Tyrannical gear had their item levels increased to ilevel 496, up from ilevel 493.
Season 13 Tyrannical Elite gear had their item levels decreased to ilevel 496, down from ilevel 512.
Battlegrounds, Rated Battlegrounds, and Arenas now have an ilevel cap. All gear will be scaled down to ilevel 496.
I think this may spawn the biggest whinedramafest of all time with 2200+ pvpers.