Upgrade to 2.0.
The major changes compared to the Turba 1.x versions are:
* Copying and moving of contacts between different address books.
* IMSP and Kolab server support.
* Access keys.
* Allow replacing address books with imports.
* Mark certain fields as required.
* Allow to group fields into tabs.
* Optional delete confirmation.
* Composite fields.
* Allow search result limits for LDAP backends.