Rated 5 out of 5 stars

You will get the not compatible with Sunbird 08, But After you do the following instructions it would be working just fine!

To make MinimizeToTray compatible with Sunbird 0.8,
you just have to edit the install.rdf file of
MinimizeToTray (Its name is probably a weired mix of
mix of characters and numbers).
The file is inside the extensions folder of your
Profiles folder (Have a look in your application data
folder).( look into your documents and settings and
then find a folder named after your own user name)

1) Open install.rdf to do some text editing.

2) Go to the section Sunbird

3) and change the max-version setting to

0.9*

4) Save the changes.

Sunbird 0.8 did not recognize the change by itself.
So you have to

5) make a backup of the whole MinimizeToTray folder

6) Uninstall MinimizeToTray (by the usual
uninstallation procedure OR just delete the folder)

7) Restart Sunbird to let it confirm the uninstallation.

8) Copy the MinimizeToTray (with its modified
install.rdf) back into the extensions folder.

9) Restart Sunbird.

And you should be good to go