Is there a free analogue of thunderbird for Windows and Linux?

Question

Mozilla Thunderbird

In the latest versions of thunderbird, the ability to run the program minimized to tray has been truncated, thus, I sometimes miss important emails.
The minimize to tray extension does not work for versions above 50, and now the current one is 50.
I'm sure that there is a good analogue, only it is difficult to find the right one from a large number of clients.
Please share your experience of using the mail client.
Thanks in advance.

Answer 1

Perhaps it will help: open the installation file of the xpi extension, for example, with an archiver and correct the line in the install.rdf file <em:maxVersion> </em:maxVersion>to the desired version or higher. After that, the extension will be installed.

Answer 2

https://www.seamonkey-project.org
In general, I recommend just installing an older ESR version.