9.9. How to add a CalDAV calendar

To set up CalDAV calendar do the following: 

1. Launch the iOS Settings app.
2. Go to Calendar > Accounts.
3. Tap Add Account.
4. Tap Other.
5. Select Add CalDAV Account.
6. Enter your service information and tap the Next button in the top right corner.
7. After your device verifies the account, you can tap Done to save the changes.
8. Launch Calendars and go to Settings.
9. Go to the Local Calendars settings menu and make sure that the CalDAV account toggle is enabled there.