A couple of days ago, my MythTV box stopped recording from the History Channel on Sky.  After some digging, I found that the transponder on 12546 has been changed from DVB-S to DVB-S2, so I updated my settings today and History is working again.  I do not watch any of the other channels on that transponder.  I do have some History channel recordings made a little before the change and by comparing them I can see that it seems that they have increased the bit rate for History a bit, but not made it HD.  It is still 1280x720 H.264.  Here is the full list of channels from a new scan of 12546 today:

It seems to just be the same channels as before, and there is no change I can see in any of the stream PIDs.  I am guessing that they will be intending to make the Arts channel HD, but as I do not subscribe to that I can not check if that has happened.

I am hoping that what we will see now is that progressively all the DVB-S transponders will change to DVB-S2.