Got a bit sidetracked.
As you note, the apnx issue should be solved for you shortly.
I have however discovered that I actually have some mbp issues myself.
mbp files are on the K3, shows book fully read, but there's no way I can get Calibre to fetch it and add to comments/library. Did have to replace my K3 in december, but other books read on first K3 show fine.