Hi Lothar,
Those are the QPP related documents that we can provide, however, you could base yourself on the implementations provided for the QN9080 in the device's SDK.
There are two implementations, one for server and one for client, provided in the package, and they can be found in the following paths:
Client: …\SDK_2.2.0_QN908XCDK\boards\qn908xcdk\wireless_examples\bluetooth\private_profile_client
Server: …\SDK_2.2.0_QN908XCDK\boards\qn908xcdk\wireless_examples\bluetooth\private_profile_server
Please let me know if you have any further questions.
Best regards,
Sebastian