For the second time this month, hence the version number, AMD has released a driver to coincide with a major game release. This one is for DOOM, which will be available on Friday. Like the previous driver, which was aligned with Forza, it has not been WHQL-certified. That's okay, though. NVIDIA's Game Ready drivers didn't strive for WHQL certification until just recently, and, even then, WHQL certification doesn't mean what it used to.
But yeah, apart from game-specific optimizations for DOOM, 16.5.2 has a few extra reasons to be used. If you play Battleborn, which launched on May 3rd, then AMD has added a new CrossFire profile for that game. They have also fixed at least eleven issues (plus however many undocumented ones). It comes with ten known issues, but none of them seem particularly troubling. It seems to be mostly CrossFire-related issues.
You can pick up the driver at AMD's website.