Seems the rumor about the switch to Unreal Engine was true after all.
At several points over the past decade, management at 343 debated switching to Epic Games Inc.'s popular Unreal Engine. But it wasn't until late last year, when previous studio head Bonnie Ross and engine lead David Berger departed and Pierre Hintze took over, that the firm finally decided to pivot to Unreal. This switch will start with a new game code-named Tatanka, according to people familiar with the plans.