Firefox just quantumed me, and they didn't ask first.
@literorrery Did you have updates set to "install automatically"?
Might be worth checking if you want to avoid further unexpected updates.
If you do want to go back, this seems to be an EXE for the previous version: https://mydownloadsoftware.com/download-mozilla-firefox-56-0-1-32bit-latest.html
@DaveHiggins Honestly, it's quite possible that I do because I want security updates without question. Somehow it escaped my mental space that "rearchitecting the entire browser" would classify as an "update" until now. I figured I'd have to go download Quantum, which I'd do once NoScript was available.
@DaveHiggins Also, the OS, Firefox, Java, and Lenovo's bios all updated in the span of half an hour when I cracked open my laptop this morning, so some of my angst right now is admittedly me feeling like everybody has stuck their fingers through the internet and _touched_ things at the moment.
@literorrery There is an intermediate setting for 'notify me of updates but allow me to choose whether to install'; so that might meet your needs. Admittedly less so in this circumstance where you're buried beneath update messages.
I empathise though: the latest driver for my laptop graphics card isn't fully compatible with my system, so I have a choice between automated updates and the screen flipping out periodically or manually checking for security updates frequently.