Downgrade package in Debian
For some reason, the recent Icedove (aka Thunderbird) version 18.104.22.168-3 in Debian does not work with the latest Enigmail version 0.95.6. No choice, got to downgrade it back to Icedove version 1.5. How ? No worries, apt is a flexible package manager, just “apt-get -t <distribution> install <package name>”.
e .g. apt-get -t unstable install icedove
Have fun !!!