Many people use a company, university or other custom cloud account (for example, hosted by ownCloud) to sync iPhone contacts and calendar events via the CardDAV or CalDAV protocols.
If you are looking to back up or extract such iPhone contacts and calendar events to your PC, follow the steps from the below demonstration.
Backing up contacts and calendars from custom CardDAV or CalDAV account
1. Download the following program on your computer
2. Start the program and connect your iPhone. Let the iPhone data load
3. Click on "More" (on the top right) then on “Cloud setup”
4. Now it’s time to connect your custom cloud account with the program in order to backup the contacts or calendars contained within the account. To do so, click “New connection” then click “Custom”
5. Enter the account username, password and server address as they appear on the account already set-up on your iPhone
Tip: You can find the account details such as the server address on the iPhone under Settings > Mail, Calendar, Contacts and then tapping on the respective cloud account you wish to connect
6. Ensure that the Contacts, Calendars and/or Reminders options are checked and then click “Add account” and exit from the “Cloud setup” window
7. Now that you connected your cloud account to the PC program, you can freely back up the contacts or calendars from the account to your computer. To back up the contacts, make sure you selected the Contacts icon from the pane on the left. Contacts synced via your custom cloud account will appear with a little globule icon to the right. Finally, click on the “Export selected” button.
You can do the same for calendars. Simply click on the Calendar icon on the left pane, select the cloud calendar and click “Export selected”.
This is the only way I know to backup custom cloud contacts and calendars synced via CardDAV or CalDAV to the computer.