No, Guid/uuids are defined as 128-bit labels used to uniquely identify objects in computer systems. This 128-bit/16-byte definition predates any RFCs that one may or may not choose to implement. I'm obviously aware of RFC 9562, and nowhere in the Guid library do I claim implementation of it. RFC 9562 is a choice, and one that should not be made blindly, or for you. It all starts with 16 random bytes. Google's uuid starts that way, and virtually every other Guid/uuid implementation. Then, on top of that building block, one may tweak additional non-random bits if the usecase truly requires it. If it does - you can do it quickly and cheaply on top of 16 random bytes. If the usecase does not require it (99% of cases), you're better off with the foundational 16 random bytes. The perspective of "your 16 random bytes do not implement RFC 9562 - BAD, BAD!" is very myopic. But if wasting bits on versions and variants is something that helps someone sleep better - they can easily and cheaply achieve that with a couple of bit ops. RFC 9562 robs developers of that choice.