sudo apt-get update && \ sudo apt-get install apt dpkg locales && \ sudo apt-get --purge dist-upgrade && \ sudo apt-get --fix-policy install && \ sudo apt-get --purge autoremove $(deborphan --guess-all)
I guess I'll be busy filing bug reports for the next few hours. Wish me (and each faulty package's maintainer) luck!
PS: Apparently, so many aspects of Debian have become dependent upon GPG features that merely upgrading APT, DPKG and libc6+locales is no longer enough. One must also upgrade gnupg and gnupg2. Thus, the second element of the above recipe has become:
sudo apt-get install apt dpkg gnupg gnupg2 locales && \
Hopefully, APT's dist-upgrade command already knows that these must be upgraded first...
PPS: Hosts running Network-Manager cannot be upgraded remotely, because Network-Manager insists upon killing the network connection and the SSH daemon with it, when its turn comes to get upgraded.