I am interested in knowing how to install an older version of thunderbird using apt-get. I have done this before using:
In the past
sudo apt-get install thunderbird=14.0+build1-0ubuntu0.12.04.1
Now using Ubuntu 12.04 when I attempt to downgrade to a specific version of Thunderbird from (thunderbird_15.0.1+build1-0ubuntu0.12.04.1)
sudo apt-get install thunderbird=15.0.0+build1-0ubuntu0.12.04.1
apt-get simply cannot find the package that I want to downgrade to. For the time being I will hunt down this older package and install it.