So, I have been looking for lots of solutions but none of them worked. I'm using Ubuntu 20.04 and want to install and update Firefox Dev automatically. I tried some ways: * By package manager: First, I uninstalled the default Firefox, removed its ppa repo then added Firefox Dev ppa and installed. Opened up and it was still normal Firefox. * By downloading .deb file from Mozilla: I could install by this way but every time has an update, Firefox will notify me "Firefox can't udpate to the latest version. Download a fresh copy of Firefox". I also have Chrome to be installed via .deb, it can update automatically. Why Firefox can't? It's very annoying that every time I open Firefox, it pops the notification up. It's impossible that every time Firefox has an update ('''which occurs regularly!''') I have to go to homepage, download then install it manually. I can write a script to update Firefox but I want an official support from Mozilla.