"We did find it challenging early on to get it to 1080p," Hight said. "That's why we made the decision to drop to 900. That's what we demoed and were showing around E3 time. And Microsoft was just like, 'This is unacceptable. You need to figure out a way to get a better resolution.' So we worked with them directly, they gave us a code update to let us get to full 1080p."
Blizzard announced during E3 that the Xbox One version of Diablo 3 would be presented in 900p, placing it at a disadvantage compared to the 1080p PlayStation 4 edition. A day-one patch pushed the Xbox One version's resolution to 1080p at launch, though Eurogamer notes that the update introduces slight framerate drops in busy gameplay areas that weren't present at 900p.
Diablo 3: Reaper of Souls (3/31/14)