Short answer: Don't know, but very likely.
In theory, all operating systems meeting the basic requirements and providing Qt 5 are supported.
I'd wonder if recent versions of Mint/Ubuntu wouldn't meet that criteria.
Of course the system tray of your desktop environment must be supported by Qt 5 and it must be correctly configured.
For the platforms (desktop environments/OS) I successfully tested checkout the README. Feel free to extend the list if you can confirm it runs under a specific platform.
BTW: This might even work under MacOS, but I have never tested and also have no knowledge about that platform.