Received this from Focusrite, thought it might be of interest here :
"Currently we are still testing Mix Control 3.6 with other Saffires with the intention of fully releasing 3.6 for other Saffires very soon.
You should be able to use 3.6 with your LS56, however please note that there may be some issues that we're not aware of. If this is the case, you can revert to Mix Control 3.4/3.5, although we'd ask that you do report the issue to us."
Great news !
Cheers,
Jerry