Coinciding with this release, Firefox 52 ESR is no longer supported, so no supported versions of Firefox support the legacy extensions.
I'm mentioning this here just so I can tell Vimperator / Pentadactyl / VimFx users that there are loads of options you can replace your old extensions with, some of which are... okay.
Links follow in increasing order of user-friendliness:
[^] Disclaimer: I develop this one. If you've tried it before in the past, now might be a good time to try it again. We've just pushed out a release that moved quite a lot of code around, hopefully eliminating a whole class of bugs, especially relating to ignore mode and multiple windows.
I'm mentioning this here just so I can tell Vimperator / Pentadactyl / VimFx users that there are loads of options you can replace your old extensions with, some of which are... okay.
Links follow in increasing order of user-friendliness:
https://github.com/tridactyl/tridactyl [^]
https://addons.mozilla.org/en-US/firefox/addon/surfingkeys_f...
https://addons.mozilla.org/en-US/firefox/addon/vim-vixen/
https://addons.mozilla.org/en-US/firefox/addon/vimium-ff/
[^] Disclaimer: I develop this one. If you've tried it before in the past, now might be a good time to try it again. We've just pushed out a release that moved quite a lot of code around, hopefully eliminating a whole class of bugs, especially relating to ignore mode and multiple windows.