MDaemon
Released on February 10, 2003. Features included:
Bandwidth Throttling, Groupware Functionality (Including: Folders for Calendar, Contacts, Tasks, Notes and Documents with Public / Private Folder Sharing), Outlook Support (Including: Email, Calendar, Contacts, Tasks, Notes and Documents with Public / Private Folder Sharing), and Meeting Requests with Automatic Updates of Attendees.
Available in the following 11 languages:
English, German, French, Spanish, Russian, Japanese, Portuguese, Italian, Chinese, Dutch / Netherlands, Swedish
Released on June 10, 2003. Features included:
LDAP Recipient Verification, and SSL / TLS / StartTLS.
Released on April 10, 2001. Features included:
Automated Old Mail and Inactive Account Deletion (Pruning), Automatic Gateway Creation When Used in a Backup MX Role, DomainPOP, Folder Sharing, IMAP Mail Filtering Rules, LDAP Account Database Backend Support, On-Demand Mail Relay (ODMR), Reverse Lookup, Server-Hosted Public and Shared IMAP Folders with Access Control Lists (ACL), and SMTP Authentication.