Thunderbird

1. Download and save the addon to your hard disk.
2. From Thunderbird, open Tools/Add-ons.
3. In the top right-hand corner you will see a drop-down - click and select “install add-on from file”
4. Locate the addon you just downloaded and click OK.

SeaMonkey

Click to download and install.

Configure

From the FAQ:

1. Check your Thunderbird proxy settings.

If your browser uses a proxy server to connect to the internet, use the same settings in Thunderbird. See Thunderbird/Tools/Options/Network/Connection.

2. Enter your login details under Thunderbird/Tools/Zindus
3. Click ‘Sync Now’

Testing Release

Want to be on the leading (but not bleeding) edge? Download the testing release to start using the release candidate for the next production release.

Release Notes

Want to know what changed? Read the release notes.