Calendar Compatibility Matrix

Sogo

Web Android iOS macOS Outlook Thunderbird
CalDav Sync - ✔ (1) ✔ (2) ✔ (3)
Active Sync - ❌ currently not working ✔ (4)
Offline use
share calendar with other
show shared calendar from other
show free busy state during meeting creation
invite a user for a meeting
invite a group for a meeting
add a meeting in a group calendar
create private meeting
add a room to a meeting

Exchange

Web Android iOS macOS Outlook Thunderbird
CalDav Sync (read only) not supported - ✔ (1) ✔ (2) ✔ (3)
Active Sync - ✔ (4)
Offline use
share calendar with other
show shared calendar from other
show free busy state during meeting creation
invite a user for a meeting
invite a group for a meeting
add a meeting in a group calendar
create private meeting
add a room to a meeting