There are a few issues in Thunderbird 31.0 that render Thunderbird useless to me.
- Find available Thunderbird versions
apt-cache madison thunderbird
- Determine which version to use
- 1:24.4.0+build1-0ubuntu1
- Downgrade to determined version
sudo apt-get install thunderbird=1:24.4.0+build1-0ubuntu1
- Send emails :D