Up to now we use tine20 for our calendars and contacts.
But some things don't work and I have the feeling that there is only little progress.
The trend looks not good: https://trends.google.de/trends/explore?date=all&q=%2Fm%2F05zw1cr
- Shared calendars
- Web GUI
- Sync to mobile devices
- Open source
Is there a good alternative?