Cognito - Sub attribute seems to be no more a valid Uuid

Hi, version 7 is a new uuid format.

See https://www.ietf.org/archive/id/draft-peabody-dispatch-new-uuid-format-04.html#name-uuid-version-7

UUID version 7 features a time-ordered value field derived from the widely implemented and 
well known Unix Epoch timestamp source, the number of milliseconds seconds since midnight 
1 Jan 1970 UTC, leap seconds excluded. As well as improved entropy characteristics over 
versions 1 or 6.

Finally, I didn't manage to get a new pool that generate Uuid v7. It seems the issue was limited in time. Maybe a problem shadow solved by AWS team ;)