Install cyrus-doc by entering the following commands in the terminal:
sudo apt update sudo apt install cyrus-doc
Cyrus mail system - documentation files
Cyrus is an IMAP server designed to handle massive quantities of mail, with a number of features not found in other IMAP implementations, including support for: - running the daemon without root privileges; - POP3 and NNTP in addition to plain IMAP; - CalDAV and CardDAV; - secure IMAP using SSL; - server-side filtering with Sieve; - mail users without login accounts; - simple mail quotas; - virtual domains; - IPv6. . This package contains the documentation for the Cyrus IMAPd suite. . For more information, please see the cyrus-common package.