Go to Options - General
Scroll down to Firefox Updates.
hmm- don’t have options panel- and in the general section there is no choice for firefox browser- i have
General
Search
Content
Aplications
privacy
security
sync
advanced-
checked them all and not seeing a browser update choice- just a search engine update chocie
Version 56 froze my Options settings including not letting me get to my logins and passwords. I got around that by starting Firefox in Safe Mode to retrieve them. Definitely time to downgrade FF 52 ESR