When I change the preferences, close the app to tray, and open it from tray again, the new preferences appear to have been saved (the UI shows the new preferences). But when I reboot, the preferences go back to before.
My investigation
By reading ~/.config/whatsapp-for-linux/settings.conf, I found that preferences are only actually saved when I explicitly call "quit". The file is only written to when the app quits, not when being closed to tray. And the file is never written to if the computer shuts down while the app is still in tray.
Encountered behavior
When I change the preferences, close the app to tray, and open it from tray again, the new preferences appear to have been saved (the UI shows the new preferences). But when I reboot, the preferences go back to before.
My investigation
By reading ~/.config/whatsapp-for-linux/settings.conf, I found that preferences are only actually saved when I explicitly call "quit". The file is only written to when the app quits, not when being closed to tray. And the file is never written to if the computer shuts down while the app is still in tray.