Dear all,
iRedMail-1.2.1 has been released with new Roundcube version (1.4.4) which
fixes few security issues.
There's no other change you should apply for server which is running
iRedMail-1.2, all users are encouraged to upgrade Roundcube as soon as
possible. Upgrade tutorial is here: https://docs.iredmail.org/iredmail.releases.html
The all-in-one dockerized edition has been updated with new Roundcube
version too: https://hub.docker.com/r/iredmail/mariadb
If you deployed iRedMail server with the iRedMail Easy platform[1], please
login to the web portal[2] and upgrade with few clicks.
Happy upgrading. 
[1] Introduce the iRedMail Easy platform: https://www.iredmail.org/easy.html
[2] Login to iRedMail Easy: https://easy.iredmail.org/