As perhaps someone may have already noticed, in Firefox, after the update to version 52, plugins no longer work, none, except the Flash Player which is the only one still supported. This means that all NPAPI-type browser plugins, such as Java and Silverlight, are no longer supported by Firefox.
The so-called NPAPI plug-ins, (which stands for Netscape Plugin Application Programming Interface) are now disabled by all the latest browsers for security reasons, so much so that Chrome which blocked the NPAPI plugins already in 2015.
The only one of the remaining NPAPI plugins that is still supported in Firefox 52 is the Flash Player, which is still too popular to be able to permanently delete it, but which will surely soon be eliminated or, at least, very limited.
In Firefox 52, going in the main menu to the Add-ons section, you can click on the Plugins and note that there are only 2 functional and active: one called the OpenH264 video Codec and Widevine Content Decryption Module provided by Google, which are not NPAPI plugins.
As for NPAPI plugins such as Java and Silverlight, the only way to continue using them is through the special version of Firefox 52 ESR (Extended Support Release), at least until March 2018.
Firefox 52 is also the latest version of the browser for computers with Windows XP and Windows Vista, which will no longer receive updates from this browser.
Note that Firefox was the only browser that still updated in these old and out of stock operating systems, which in the future will no longer have a safe browser for surfing the internet.
For these PCs, the Firefox 52 download will remain active (should) even after the release of Firefox 53.
