Basically, it provides a mechanism for a server to sync calendar data with multiple clients.

Using CardDAV and CalDAV protocols, users can keep their contacts and calendar data in sync, and it’s very easy to set up. CalDAV can be set up in almost the exact same way as CardDAV on your Apple (iOS & OS X) and Android device, and all it requires is a SpinOffice account with the DAV activated. 

After activation in SpinOffice you will receive an email in which we describe the steps how to set up the DAV sync account on your Apple (iOS & OS X) or Android device.

If during configuring or connecting to the CalDAV account on your iPhone, iPad or Android device the 'CalDAV account verification failed' error is displayed, then there is an authentication problem. Read here how to solve this.