Unlikely. They support only two full ESRs.

Please explain the problem in detail. What happens? What is/are the exact error message(s) ?

I can login to the Firefox account with Firefox 52, but I can't access the Firefox Account settings page.

• https://accounts.firefox.com/settings?service=sync&entrypoint=preferences

Web Console:

• TypeError: Object.fromEntries is not a function

There are no Sync error logs and a Sync success log (about:config => services.sync.log.appender.file.logOnSuccess = true) looks OK.

I didn’t like where Firefox Quantum was going. So, I stopped updating at v54. The sync settings are located at; about:preferences#sync