FairPlay DRM license acquisition mechanism

Hi! We're trying to implement FairPlay DRM on one of our assets (we're using Unified Streaming for on-the-fly encryption of our assets and Irdeto as our partner company to implement the FairPlay license server), and I see that JW Player does a GET request to the license server to acquire the license information. Is this standards-compliant with FairPlay? Irdeto claims it should be a POST request, but JW Player does a GET request by default, and we don't have access to the FairPlay SDKs or documentation so we cannot verify what it should be. Regards Thane