StackRegent 0.17.18
Webmail over HTTPS for domains whose website is hosted elsewhere: when only mail and webmail.<domain> point at this server, webmail.<domain> can be ticked under Let's Encrypt on the website's SSL/TLS page (and free SSL adds it by itself); the webmail then uses any certificate of the subscription that covers it. Domains with mail also get webmail.<domain> offered for their own certificates.
How to update: in the administrator panel, open Tools & Settings → Updates, click Check now, then Install. Websites, mail and DNS keep running while the panel updates. SHA-256 of the package: 9bd365cdb1483680afc901b36a20939ba3e42db6dccedd207d5db6f5ef84769d