Mailbox for Linux

Version 0.1.25, as a Flatpak. Installing it also subscribes this machine to the update repository at https://tlmb-flat.2615.io/repo, so it keeps itself current.

flatpak install --user https://tlmb-flat.2615.io/tlmb.flatpakref

Or download the single-file installer and open it. Either way, updates come from here.

Source