
Use Safari presumably the school site supports those browsers. #Unfortunately even that will eventually change to ESR 24 so you then should use some other browser entirely if your school site is not updated before that change (next year). Mozilla has published Firefox 22, you can download it over here or wait for the automatic update if you already have Firefox. Check your Firefox version (in the About Firefox window) and look for (32-bit) or (64-bit) after the version number: If you see (32-bit) and you are running Firefox 56.0 or older, updating to the latest Firefox version.
DOWNLOAD MOZILLA FIREFOX 22 HOW TO
(This is not an officially sanctioned and supported method, it is however safer than downgrading to Firefox 22: that is dangerous ! ) Well, you can download the online installer for Firefox from its official website. If you’re running 64-bit Windows ( here’s how to check ), your Firefox may already be 64-bit.

DOWNLOAD MOZILLA FIREFOX 22 INSTALL
As an additional browser install and use the unofficial Firefox Portable ESR that will use a secure version of Firefox17 that should be compatible with your school site. Mozilla Firefox is a free, fast and efficient cross-platform web browser and one of the most popular browsers in use.Important: By default, Firefox is set for automatic updates. Continue using Firefox 23, soon to become Firefox 24 for day to day browsing Directory of other versions and languages.You may be ok using Firefox 22 on only the school site, but you should be using an updated browser for day to day browsing.

I did indeed find instructions on your school site to uninstall Firefox 23 and instructions to install Firefox 22
