What is the meaning of releaseCompleteReason=invalidRevision in RELEASE COMPLETE? Does it mean invalid revision of H.225.0? Or is it more general (like invalid versionId in the vendorId field for example). I suspect it is supposed to mean invalid revision of H.225.0. It isn't documented in H.225.0 (or H.323). I also suspect that if you want to do anything fancy like rejecting a call based on vendorId/productId/versionId, you'd should use the nonStandardReason?