[stevesimmons]

To summarise the differences:

* UUIDv6 - sortable, with a layout matching UUIDv1 for backward compatibility, except the time chunks have been reordered so the uuid sorts chronologically

* UUIDv7 - sortable, based on nanoseconds since the Unix epoch. Simpler layout than UUIDv6 and more flexibility about the number of bits allocated to the time part versus sequence and randomness. The nice aspect here is the uuids sort chronologically even when created by systems using different numbers of time bits.

* UUIDv8 - more flexibility for layout. Should only be used if UUIDv6/7 aren't suitable. Which of course makes them specific to that one application which knows how to encode/decode them.

UUIDv7 is thus the better choice in general.

(I recently wrote Python and C# implementations - https://github.com/stevesimmons/uuid7 and https://github.com/stevesimmons/uuid7-csharp)