As has been reported in other posts on this and other forums. It is not a new codec, it is not pairing, it is a new control word encryption process.

There is no technical reason why this new control word encryption process could not be rolled out any encrypted HD channel - but BBC1 HD etc are fta and not subject to control words.

There is a (presumed) technical reason why this new control word encryption process will not be rolled out to SD encrypted channels, as it is believed the old SD boxes are not secure.