Zimbra Collaboration is the world’s leading open source messaging and collaboration solution. Zimbra includes complete email, contacts, calendar, file sharing, tasks, and messaging/videoconferencing, all accessed from the Zimbra Web Client via any device. You can deploy Zimbra as a traditional on-prem install or through a Zimbra hosting provider. Zimbra also has enterprise-level chat and video calls, so you can communicate with your team no matter where they are.
Zimbra Collaboration Reviews