I was using mail-notification for a long time, but it stopped working lately. The AUR maintainer is trying to fix it, but the project is dead for years, so it's expected that it'll cause more and more problems in the future. Hence I'm searching for something still maintained.
My requirements are:
Works under XFCE.
Displays an icon (in system tray or on a panel) when new mail is available. When there is no new mail, nothing (neither icons, windows nor other things) should be displayed.
Displays notification about new mails.
I've checked various applications, but none of them fulfills those requirements.