This is the latest version of Firefox, and was released earlier this month. The upgrade to the older version on my laptop happened earlier today, and it annoyed me - mostly because the toolbar, etc, had been moved, and there was no way to customise it to put things back to where I wanted them to be.
Having done some googling, I found this article: www.computerworld.com/s/article/9248310/Firefox_UI_revamp_sparks_complaints_searches_for_alternatives and I downloaded Pale Moon, which not only has everything in the places I originally had in Firefox, but seems as customisable as the older Firefox.
I thought I'd post this here, just in case anyone else has the new version of Firefox and doesn't like it.