Same here (but unfortunately in german). But i tried this:
$ sudo -i # LANG=en_US apt-get install -f
et voila: it removes libmtp5 and installes libmtp6
Same here (but unfortunately in german). But i tried this:
$ sudo -i
# LANG=en_US apt-get install -f
et voila: it removes libmtp5 and installes libmtp6