Falcon Manufacturer Sdk 6.1 KnxBus.Unlock fails

We have updated Falcon Manufacturer SDK from version 5.7 to version 6.1. Unfortunately, unlocking with KnxBus.Unlock is not working. The callback method from KnxBus.Unlock is not being called at all. The Manufacturer ID and public key in the knx_master.xml are correct. However, the Purpose attribute of the PublicKey tag contains an empty string instead of 'Falcon.' What are we doing wrong? Do we need to register again for version 6.1?

Thanks in advance and Best Regards.

Anton Rohrwick
Alexander Maier GmbH