---
type: concept
title: DAV Synchronization
tags: ["protocol", "synchronization", "groupware", "protocols"]
related: [groupware]
created: 2026-07-01
updated: 2026-07-01
sources: ["output/rz_uni_greifswald_de_dienste_webdienste_groupware_sync.md"]
---

# DAV Synchronization

**DAV Synchronization** is the technical method used by the Universität Greifswald Groupware system to synchronize calendars, address books (contacts), and tasks between the central server and external client applications.

## Protocols
The system utilizes two specific extensions of the DAV protocol:
- **CalDAV**: Used for the synchronization of calendar events/data and associated task lists.
- **CardDAV**: Used for the synchronization of address book (contact) data.

## Operational Constraints and Limitations
- **Manual Resource Activation**: Synchronization is not automatic upon client configuration. Users must first manually enable/select the specific resources (calendars or address books) within the Groupware web interface under **"My Account" $\rightarrow$ "Synchronization"**.
- **Temporal/Historical Window**: CalDAV synchronization is not unlimited; it synchronizes all future events and a historical window of up to **12 months**.
- **Task Management**: Because task lists are logically and technically linked to calendars, they must be configured via the calendar administration settings/interface.

## Platform-Specific Issues
- **Android Deletion Bug**: A known issue in the Android operating system prevents the synchronization of deletions from the client to the server (preventing the deletion of items via synchronization by default). To resolve this, users must explicitly enable the **"Allow deletion via synchronization"** option in their Groupware account settings.