Mozilla no longer supports Silverlight, Java and Acrobat in the latest version (52) of Firefox. According to the browser developer the plugins are responsible for performance issues, crashes and security issues because they make use of the old Netscape Plugin API (NPAPI).
Firefox will continue to support Adobe Flash Player, which uses the same API, because it’s still frequently used on the internet, according to Mozilla. Nevertheless it plans to eventually phase out support for Flash in the browser. Users who really require NPAPI plugins are advised to switch to a Firefox Extended Support Release. This version will continue to support plugins like Silverlight and Java for some time.
With the release of Firefox 52, the browser will now also warn in case websites use an outdated and now insecure SHA-1 certificate. Firefox will indicate that the connection is insecure but provides users the option to ignore the message.
Users on Windows XP and Vista are now automatically upgraded to Firefox Extended Support Release (ESR) as Mozilla no longer actively develops for these outdated Windows versions. The ESR version of Firefox only receives security updates. In September this year Mozilla will pull the plug on both the XP and Vista version of its browser, the company will start warning users before that happens.
Firefox will from now on also warn for insecure login forms on regular HTTP pages. The browser will show a notification that the connection is insecure when users fill in their username and password on a non-HTTPS page.
Firefox 52 can be downloaded from the Mozilla website but most users will be automatically upgraded.