Native support for iCloud now in the new Thunderbird version.
The new version of Thunderbird now support iCloud accounts directly.
Video
Integrate iCloud calendar in Thunderbird
Let’s test this out. We create a new calendar and select “On the network”.
In the next step, we enter our username and the CalDAV address. We use the following address:
https://caldav.icloud.com
In the Apple ID settings page we need to create an app specific password, which we can use. The password is automatically generated.
If everything went well, the calendars are now displayed and we can select them from the list.
Thunderbird now synchronizes with the iCloud calendar.
iCloud: synchronize contacts with Thunderbird
The procedure for contacts is similar. We add a new CardDAV address book in the contacts.
We enter username and password. The password needs again to be generated like shown above.
Done, the contacts are now synchronized.
Conclusion
Very nice, the function is now built directly into Thunderbird and we no longer need any extra extenstion for the software.