Dav apps

Android

Contacts and Calendar

• DAVx⁵ - https://www.davx5.com/  or https://f-droid.org/en/packages/at.bitfire.davdroid

Thunderbird - Add-ons

Contacts

• CardBook

Calendar

• Lightning

Microsoft Outlook

• Outlook CalDav Synchronizer - https://caldavsynchronizer.org/download-2/  or https://github.com/aluxnimm/outlookcaldavsynchronizer/releases