Many sites broke with Firefox 28 due to missing features.
Most sites added version checks and would bounce you to an "update your browser" screen, but most worked just fine by faking the user agent version.
Sites like Dropbox, Patreon, etc would fail to render though. The version hack had the sites trying to use features it didn't really support.
Version 29 was the first to turn the UI into a Chrome imitator, and "Classic Theme Restorer" never got close to matching the actual look and feel of version 28. Especially not on Linux/BSD. I also resented having to use a bulky extension (that will stop working when Firefox drops XUL extensions) just to change really basic UI options like "don't put refresh on the right-hand side of the address bar."
What specifically bothers you about Australis? I hate what it did to tab layout, but that's the only part that's chrome-like and can be fixed with a bit of CSS, no extensions at all. It set up a new weird one-button menu, but firefox already had a weird one-button menu, and they never removed the ability to use the normal menu bar and ignore the button. And that menu is less chrome-like than the one it replaced.
I want a regular title bar in my application with the full title of the current tab.
I don't want rounded curves on my tabs. I'd rather they just look like normal tabs.
I want the tab bar beneath my address bar. Australis removed tabsOnTop=false.
I want back and forward to be separate buttons, and not integrated into the address bar.
I don't want the refresh button on the right-hand side of my address bar. I want it after the back/next buttons.
Firefox 28 with tabsOnTop=false is what I want. Classic Theme Restorer gets me there, but with rendering issues, especially on Linux/BSD. And Mozilla already has plans to kill it when they remove XUL extensions.
None of the Australis changes increased usability. They just changed things for the sake of it, and took away a lot of flexibility in customizing the UI layout. I have a lot of difficulty changing up the way I use programs. I've had the same browser layout for 15 years. Nothing wrong with it. I don't want to retrain muscle memory all the time because some designer at Mozilla was bored.
I'm not the kind of "works on my machine" developer so I'm sure that if this was your experience something actually happened. But what?
Firefox 28 is from March 2014. I don't remember sites suddenly stopping working at any time, so it could be that I'm not using some of the features you started missing. Which features did Firefox 28 remove or which missing ones in FF went mainstream on so many sites 3 years ago?
I really don't remember any "update your browser" prompt with Firefox since when web sites were insisting to support only Internet Explorer 6 and Firefox was starting to take off.
