Most of the add-ons should work up to version 54. With version 56 they start having issues. And version 57 will not run many of the add-ons that we have come to know and love. Over the last few years, Mozilla developers have been removing things from this excellent browser. The removed the add-on bar from the bottom of the browser window despite the fact that some add-ons need it to work. The removed plugin support. While many are not affected, a large number of users have complained. And now they have removed many add-ons from being able to run at all. Hi, The people who answer questions here, for the most part, are other Firefox users volunteering their time (like me), not Mozilla employees or Firefox developers. If you want to leave feedback for Firefox developers, you can go to the Firefox ''Help'' menu and select ''Submit Feedback...'' or use [https://qsurvey.mozilla.com/s3/FirefoxInput/ this link]. Your feedback gets collected by a team of people who read it and gather data about the most common issues. -------------------- https://support.mozilla.org/en-US/kb/install-older-version-of-firefox?cache=no Be sure to read everything here. If you still want to downgrade, look under; '''I still want to downgrade.''' Click the '''Directory of other versions and languages''' link. Look for the directory of the version that you want. But, remember that old versions may have security issues. You should also check out [https://www.mozilla.org/en-US/firefox/organizations/ Firefox; Extended Support Release] {web link} [https://www.mozilla.org/en-US/firefox/organizations/notes/ ESR Notes] [https://www.mozilla.org/en-US/firefox/organizations/system-requirements/ System Requirements]