The potential problem there is that a Canon R body will require an adapter to use the lens. That adapter could block the shift. See what Canon says, but I'm guessing they will recommend the older bodies too.
Another possible solution, one that worked for me with the Canon 5D and might work with later models; is that the camera has a second back up battery that many people are unaware of. It's very well hidden under the corner of the camera bottom on one ...
