Ronald F. Guilmette via db-wg wrote on 08/06/2021 00:48:
The last time I checked, there was nothing within any of the relevant RFCs that explicity stipulated that the user-id portion of an email address either SHALL or MUST or SHOULD be treated as case insensitive
the <local> part of an rfc821/rfc2821 email address has always been case-sensitive.
Otherwise, almost all if not all tokens in ripe181++ syntax are case insensitive, and always needed either case translation or case-insensitive comparison to process correctly.
Nick
