Mozilla launches a stable version of Firefox 64-bit for the Microsoft Windows operating system this month in silent fashion. While it is available for download, it is not yet listed on the organization's official download site .
Firefox users can download the 64-bit version from Mozilla's Download Archive though. Since it is the first official stable release, it is likely that Mozilla wanted to monitor bugs and other issues for a release cycle.
One core difference between the 32-bit and 64-bit version of Firefox for Windows lies in plugin support.
Firefox 32-bit users can install plugins like Java, Silverlight or Adobe Flash and they will get picked up by Firefox automatically.
64-bit versions of Firefox on the other hand accept only Adobe Flash and no other plugins even if 64-bit versions of plugins are available.
This is going to change soon however as Mozilla plans to add Microsoft Silverlight to the browser's whitelist.
The reason given is that streaming services such as Amazon or Netflix, as well as several local streaming providers such as Eurosport, Videoload, Sky Go or Magine TV use Silverlight exclusively or optionally.
Mozilla plans to integrate support for Silverlight in 64-bit versions of Firefox in Firefox 43 or 44. It is not clear right now if the organization manages to add support of Silverlight in Firefox 43, to be released on December 15, 2015 , or Firefox 44, which will be released on January 26, 2016.
No 64-bit version of Firefox for Windows picks up the plugin currently.
Support for Microsoft Silverlight will be temporary only, as Mozilla announced some time ago that it will retire NPAPI support in Firefox at the end of 2016 .
This ends support for Flash, Silverlight and other browser plugins that depend on NPAPI in all versions of the Firefox web browser.
It is interesting to note that Firefox is one of the few mainstream browsers left that supports Silverlight. Neither Google with its Chrome browser nor Microsoft's new browser Edge support Silverlight anymore.
This leaves users with two options. First, they can block updates of the browser to retain plugin functionality, or keep an older copy around for that purpose, or they may use a browser that won't discontinue support. Pale Moon for instance won't follow Mozilla, Google and Microsoft according to a post on the official forum .Closing Words
I think that browser developers should leave it up to the user to install and use plugins, provided that they don't cause instabilities or have known security vulnerabilities.
That does not mean that they cannot protect their users by default, for instance by setting plugin contents to "click to play" instead of running them right away. (via Sören Hentzschel )
Now You: Do you use Silverlight?Summary
Firefox 64-bit to support Microsoft Silverlight after all
Mozilla will add support for Microsoft Silverlight to 64-bit versions of the Firefox browser on Windows in Firefox 43 or 44.