Kolab Community

Kolab Groupware is a secure, scalable, reliable, flexible, full-featured collaboration suite.

20 Alternatives To Kolab Community

Citadel

Is a collaboration suite (messaging and groupware).

Lightning Calendar

Organize your life — it’s about time!

Mail-in-a-box

Mail-in-a-Box provides webmail and an IMAP/SMTP server for use with mobile devices and desktop mail software and also includes contacts and calendar synchronization.

Microsoft Exchange Server

Microsoft Exchange Server is a messaging and collaborative software product developed by Microsoft.

Proxmox Mail Gateway

Protect mail server against spam, viruses and malware with Proxmox Mail Gateway security for businesses, government, education and non-profit organizations.

Rainlendar

Rainlendar - Customizable desktop calendar

Simple Calendar

A simple calendar with events (optional recurring and reminders), week numbers and a customizable…

Zimbra Collaboration Suite

Zimbra Collaboration is an open, secure collaboration tool for email, calendaring, tasks and more.

mailcow dockerized

An open source mailserver suite.