@ElectricKeet I have a solution for this (just tested it) if you need one.
@ElectricKeet User-agent spoofing is what I did; just take the "Waterfox/53.0.1" bit off the end there.
Y'know, my first impulse in this whole thing was to make a (minor, gentle) case in favor of "One has to draw the browser-support line somewhere, for the mental health of support folks if nothing else" but if they're doing this sort of picky-ass user-agent check to determine what's supportable and what isn't, that's pretty fucking inexcusable. :P
@indi See, that's the thing. They want Firefox 47+ – which means that if I downgraded to a less-secure DRM-encrusted home-phoning browser, they'd be happy! PROGRESS.
It's one thing to say, "Use whatever borwser, but we can't offer technical support if it isn't one of these." That's very understandable. Locking everything else out isn't helping the user, though.
*sighs* Granted, I'm also a bit grumpy this morning, but I'll get over it. Thanks for your help. *hugs th' plush*
@indi I suppose I do, thank you. I hadn't gotten around to testing user-agent spoofing; I wanted to get some other work done first.