Apple Is Testing a Four-HomePod Surround System, Code Suggests

Apple appears to be working on some major new HomePod home theater features, including a four-speaker surround sound system and a new "Party Mode," according to code found in audioOS 27 beta 8, and shared on the MacRumors forums by member pdfu.
References in the software for the second-generation HomePod suggest the ability to tune for a setup with front-left, front-right, rear-left, and rear-right HomePods. The four-speaker surround configuration references automatic room calibration, speaker-p