I've been using Firefox with my iMac OS 10.11.6 El Capitan I can't update my OS on my otherwise perfectly operational iMac. Firefox was working for me where other browsers wouldn't. Today I was invited to update my firefox system through a website I was visiting. I took up the option without giving attention to the 'No-Go' icon and stupidly replaced the Firefox version I had, Now I have no working firefox option and I cant locate the older version. I understand the security risk but my Mac system, my expensive internet service provider and my own usual caution around internet use, and my awareness of spam and phishing messages have so far protected me on the web. I'd be very pleased to be able to use the Firefox version that will work with my OS 10.11.6 but I don't seem to be able to find a suitable download. Can you assist me please albeit entirely at my own risk