Please allow us to download older versions. I use FF for primary web development because of the great tools available. When FF updated I kept my version at 55 to keep my tools working. I neglected to set this extension to 'do not upgrade'. Now 2.01 on FF 55 crashes when I try to use VIEW CSS. I can't find a way to revert to an older version of this extension. It's a crippled version of what once was.