https://www.plesk.com/blog/product-technology/shell-checkpassword-authentication-in-dovecot/
CheckPassword authentication in Dovecot: a practical example in Shell - Plesk
Mar 18, 2019 - A basic guide on how to set up authentication in Dovecot via custom CheckPassword script written in Shell
a practical examplecheckpasswordauthenticationdovecotshell
https://dovecot.org/mailman3/archives/list/dovecot@dovecot.org/thread/NHUN56TEDA4VBLJTOE7GRHKROTM6ZJXB/
managesieve & checkpassword authdb interface - dovecot - dovecot.org
managesievecheckpasswordinterfacedovecot