I would like to mention:
Before updating to this version backup your own customized accelmap.conf in .mypaint because it will be overwritten. That is, if you want to keep your own mappings...
EDIT: This does not seem entirely true. It does get regenerated which means the default shortcuts are changed but the custom shortcuts will stay intact.

AapoRantalainen, any idea why reordering brushes by dragging does not work?
Did you consider changing the brush icon size in the brush selection window to 72 pixels?

Thanks again...