This is a meta commit for a feature originally implemented in 0a970aef8a documenting the change from using the username as a subject identifier to a specification compliant subject identifier in the form of RFC4122 UUID V4 subject identifiers. This is a required change in order to be compliant with the specification as per https://openid.net/specs/openid-connect-core-1_0.html#SubjectIDTypes. Relying parties which utilize the subject identifier / sub claim may need manual intervention in order to relink accounts. Users who have issues will have to consult with the documentation of their individual relying parties in order to relink accounts. Users who utilized the subject identifier as a means to provision their users are also encouraged to utilize the preferred_username claim from the profile scope.