I have trying to find how to set the dovecot-sql.conf for using SHA256/512. I am going to start clean with the stronger format, not migrate from the old MD5. It seems all I need is:

driver = mysql
connect = host=/var/lib/mysql/mysql.sock dbname=postfix user=postfix password=$Postfix_Database_Password
default_pass_scheme = SHAxxx-CRYPT
# following should all be on one line.
password_query = SELECT username as user, password, concat('/home/vmail/', maildir) as userdb_home, concat('maildir:/home/vmail/', maildir) as userdb_mail, 101 as userdb_uid, 12 as userdb_gid FROM mailbox WHERE username = '%u' AND active = '1'
# following should all be on one line
user_query = SELECT concat('/home/vmail/', maildir) as home, concat('maildir:/home/vmail/', maildir) as mail, 101 AS uid, 12 AS gid, CONCAT('*:messages=30000:bytes=', quota) as quota_rule FROM mailbox WHERE username = '%u' AND active = '1'

where xxx is either 256 or 512. All the rest I have been finding in my searches concern converting the format and are not needed for a clean start?

thanks