* ricccardo: > ric@ricmbp:~$ dpkg -l | grep libnss > ii libnss3 2:3.13.4-3~bpo60+1 Network Security Service libraries > ii libnss3-1d 2:3.13.4-3~bpo60+1 Network Security Service libraries - > transitional package These packages do not come from the stable distribution. You're using backports, presumably for iceweasel. Upgrades in backports are not as seemless as they are for the stable distribution because they reflect active development.