On my current mail server I was able to upgrade everyone?s password scheme to ARGON2ID with no issues, I just had to have: service auth { vsz_limit = 0 } This was an older version of macOS than the new server I?m trying to migrate to. The new one has Dovecot compiled with same configure options, same configuration files, but fails to authenticate: Feb 21 21:51:03 master: Info: Dovecot v2.3.20 (80a5ac675d) starting up for imap, pop3 (core dumps disabled) Feb 21 21:51:33 auth-worker(11701): Error: conn unix:auth-worker (uid=214): auth-worker<1>: sql(jlbrown at bordo.com.au,::1,<bRgbkDP2udEBAAAAAAAAAAAAAAAAAAB>): Unknown scheme ARGON2ID ./configure --with-ssl=openssl --with-mysql Was what I used to compile. Using OpenSSL 3.0.8. New server is running macOS 13.2.1 Ventura. (Have also installed libsodium 1.0.18_1) Any help would be most appreciated. thanks, James.