So, Firefox decided to drop support for “old technology” plugins… Since I could not find web-extension updates for some of my required plugins or they are not ready yet (e.g. Tab Mix Plus, now called Tab Mix – Links)…
Easy-peasy: install ESR 52.9.0, then disable auto-updates… Done!
Not quite… I booted my PC this morning only to find Firefox, flicking a big middle finger to all its advanced users, had ignored my settings to not auto update – and proceeded to update itself to ESR 60.2…
Obviously, this got me royally pissed as I had to waste time rolling back and setting it up as I originally chose (i.e. no updates); and so I wasted some time to track down and neuter their update capabilities once and for all.