A report on Bloomberg (may require registration or subscription) by Jason Schreier has more on the recent shakeup at Halo: Infinite developer 343 Industries. This confirms the report that the company remains the primary developer on the Halo franchise after rumors said otherwise. But it also notes that with deep cuts to its staff and the switch to a new engine, 343 is basically "starting over from scratch" with the shooter series. Here's more on plans to pivot to the Unreal Engine:

Chief among them is a pivot to a new gaming engine, the suite of tools and technology used to make video games. The studio’s own engine, known publicly as Slipspace, has been one of the biggest points of contention over the past two decades. Based largely on old code from the 1990s and early 2000s, it’s buggy and difficult to use and has been the source of headaches for some developers on Halo Infinite, people familiar with the development said. Several multiplayer modes that are nearly finished, such as Extraction and Assault, both popular in previous Halo games, have yet to be released in part because of issues involving the engine, they said.

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. That project, which 343 is developing alongside the Austin, Texas-based game studio Certain Affinity, started off as a battle royale but may evolve in different directions, the people said. Future games in the series will also explore using the Unreal Engine, which may make development easier, although internal skeptics are worried that the switch may have a negative impact on the way Halo games feel to play. A Microsoft spokesman declined to comment on issues with the engine or on the company’s plans to pivot to Unreal.