I’m trying to experiment myself with alternative solutions for O365. The first good candidate I think is Kopano Groupware.
- Kopano page: https://kopano.com/
- Download Univention server + Kopano appliance: https://kopano.com/downloads-demo/?demo=Kopano+ONE&headline=Appliances&target=Univention
- The good thing is Kopano solution is integrated with Univention Corporate Server (UCS) which also allows us to set up an Directory service like AD, setup DNS, Filesharing etc. And all are managed via Web interface.
I set it up on a Virtual Box VM and played around. With Kopano, I tested email service and Video/Audio conference
Email and Calendar seems good, I’m using Web app but there’s also Desktop app version.
Information Technology and more 