The <em>regular release</em> of Firefox 52-53 only allows one plugin, which is Flash. The <em>Extended Support Release</em> (ESR) of Firefox 52 will still run Java, and other old plugins that ran in Firefox 51. ESR was first developed to meet the needs of large organizations that wanted Firefox to change much more slowly. It gets security updates but no feature changes for about a year at a time. You don't have to be in a company to use it. More information on this change and ESR: [[Why do Java, Silverlight, Adobe Acrobat and other plugins no longer work?]] When you get to [https://www.mozilla.org/firefox/organizations/all/ the ESR installer list], you'll notice at least two different downloads for Windows: <ul> <li><strong>Windows</strong> installer is the <strong>standard version for Windows</strong> that runs on both 32-bit and 64-bit Windows Vista through 10 (and 32-bit XP), the best choice for most users</li> <li><strong>Windows 64-bit</strong> installer ONLY runs the Flash and Silverlight plugins, so that may not be what you're looking for. (If someone reading this only needs Silverlight and is considering switching to 64-bit, there may be some extra file cleanup to do on your system. See: [[How to switch from 32-bit to 64-bit Firefox]].)</li> </ul> When you run the ESR installer, it should detect your existing settings folder and do an "update-type" installation. However, it doesn't hurt to make a backup first: [[Back up and restore information in Firefox profiles]].