The developer of the FireTray for Thunderbird extension no longer releases updates and it’s not compatible with the current version of Thunderbird. However, to keep Thunderbird from hanging constantly in the taskbar, there is a way to install this extension.
Here’s how to do it (correct for other extensions, but you have to do it at your own risk, not the fact that everything will work properly and without any harm):
Select “add-ons” from the menu, then “extensions”, and type a “firetray” in the searchbox. Next, click “See xxxx results” and find out it in the search. Hover the cursor and click “View other versions.” Click “Download for Windows” next to the latest version, the file with the xpi extension will download. Open this file with an archiver, for example Winrar, and edit the install.rdf file inside – find there such a block related to Thuderbird:
<em:targetApplication> <!— Thunderbird —>
Type a number greater than your version of Thunderbird after <em: maxVersion>.
Click the button with a gear on the extensions search results page (where we pressed “View xxxx results”), and select “Install add-on from file”. Choose our xpi file and install it.
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