Q on versioning mechanisms for RTP payload headers in H.245

I remember past discussions on using dynamic payload types for H.263+ last year, but has there been any effort going on in H.245 to add a field to video capability structures that would allow a sender endpoint to determine before hand if the receiving endpoint can receive H.263 data with a particular version of a payload header?

Is a general versioning mechanism for RTP payload headers in the works for H.245?

-Regards,

Philippe Ferriere Microsoft Corp.