edit: Indeed, that's the firmware revision credential management was added, per this blog post: https://www.yubico.com/blog/whats-new-in-yubikey-firmware-5-...
I'm honestly very annoyed with Yubico that they just froze their product line-up circa 2018 and pretend the major changes in firmware (5.2, 5.7) don't matter at all and don't warrant a separate SKU.