Except re-saving in .exr with Photoshop (with Nuke it doesn't work, even with the same parameter than PS) and re-import everything (File > Import Surface). We don't have any way to edit .json easily either, I hope you will re-add jpg/png compatibility for displacement.
I've created some custom material for studio (with custom textures) before the last update (0.911), back then Studio support only .png, but now my material doesn't work anymore. Even if I convert my .png in .exr with Nuke, same problem (my export setting maybe ?), and if I find the solution I have to do the conversion for…