Just gave the v16 vikunja-desktop appimage a spin (on manjaro linux).
Started fine, was able to login ok (once I remembered to use my api url not the frontend url, oops). But twice it’s just started spinning its wheels and failing to talk to the server, doesn’t do that in the browser.
Logging out and logging in again seems to fix it, but since the desktop app doesn’t remember url/username/password that gets a bit painful.