Iam Using Lync Server with UCWA 1.0 and have several questions about the Endpoint ID.
Thanks!
Specifically related to UCWA for On-Premises
The Endpoint ID is just a string ('blablabla' is a valid Endpoint ID), you don't have to register it anywhere. Trust is given to your application via Set-CsWebServiceConfiguration
Yes
I think there is no documented limit, but should follow the number of max active endpoints the user can have (including logged in clients). Anyway, also in relation to question above: if you create two UCWA applications for the same user and same endpoint ID, you'll receive a conflict, and one application will be terminated
As per first answer: in this scenario Endpoint ID is just any valid string, and not registered anywhere with the server (thus no validity expiration)