Hi, simple Firefox 51 is not supported and you do not have appropriate plugins to do anything on XP.

• https://support.mozilla.org/en-US/kb/end-support-windows-xp-and-vista

Possibly where you should be and also running is 52.7.3ESR It will continue to get security updates until June 2018, and you can download and install it from this page:

• https://www.mozilla.org/en-US/firefox/organizations/all/

Note : Legacy Extensions will be deleted or removed in any version update after June 2018. Firefox 52.9.0esr out on June 26 (same time as 60.1.0esr) will be the last major update for Firefox 52 ESR apart from any 52.9.x esr updates for security or allowed stability fixes.

Firefox 60.2.0esr based on Quantum will be out Aug 21 and Firefox 52 ESR will be EOL then. So people will have to upgrade to 60.2.0esr to keep getting security updates if they have not manually upgraded to 60.x.o ESR already. Firefox 60 ESR will require Windows 7, 8, 10.

You should make a backup of your Profile just because:

• https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles
• https://support.mozilla.org/en-US/kb/export-firefox-bookmarks-to-backup-or-transfer

No answer for your issue as unsupported and to old.

Please let us know if this solved your issue or if need further assistance.

Daniel_San said

In contrast, when I try to watch the same stream on my Windows XP computer (with Firefox Portable 51.0.1, too), I am asked to install Silverlight. Why does this happen? At Windows 7 it seemed that it got streamed via HTML5, I didn't have to install Silverlight. I installed the same three modules listed above, setting the appropriate flags in about:config, etc. In Plugins I find some more listed, like Microsoft DRM, etc. I don't understand why DAZN behaves differently, depending on which Windows OS I open the platform, how can this happen? Afterwards I even installed Silverlight, but the page reloads periodically, each 1-2 seconds, showing a few video frames, before it reloads again. Additionally, the dialogue appears over and over again, asking if I would like to allow Silverlight. It can't be any Silverlight issue, because Silverlight works fine on another platform (SKY GO). I would appreciate some technical insight into this, because I have no idea/explanation what's going in and how I can get this started on Windows XP. At least I want to understand the different behavior.

The not being able to play HTML5 player stuff on WinXP is due to Microsoft not supporting the old EOL WinXP with the media feature pack stuff (as they do with Vista and later) as it provided codecs needed for the HTML5 player to be fully used in Firefox and SeaMonkey. You can test at https://www.youtube.com/html5/

Sites like Youtube has not used the Flash Player as a fall back for months now on current videos and many other sites are using a HTML5 player to be more cross platform compared to just using Flash Player Plugin which has more limited device support now in comparison.

With some workarounds you may be able to use HTML5 player in Firefox/SeaMonkey on WinXP. http://www.msfn.org/board/topic/175591-enable-mp4-h264-aac-html5-video-in-firefox-on-windows-xp-without-flash/

First of all, thanks for your feedback. @Pkshadow: Thanks for the firefox support notes and deadlines, that's really useful. As already pointed out, it works with Firefox 51.0.1 on the Windows 7 computer, I also tried with V52.7.3, same issue. @james: I was already aware of the msfn article, and I did already follow the instructions. The weird thing is, as I did already mention, that I am technically able to watch HTML5 videos (it is approved at the youtube html5 testpage), but still, it is not working on DAZN.

I did some further investigations, opening the stream on the Windows 7 computer once more, and found out, that the Silverlight notification only appears with the Widevine content decryption module deactivated. While Widevine is not compatible with Windows XP, i did follow the instructions on MSFN to activate Adobe Primetime. But it seems that DAZN is not working with Adobe Primetime, right? Otherwise it wouldn't have asked for Silverlight. When I got the notification, I installed Silverlight, but as mentioned it reloads each 1-2 seconds. Thus, I would not need Silverlight, as already expected, to watch the stream, but unfortunately I have no explanation why Adobe Primetime is not working then? Do you have any suggestions what I could test? Keep in mind, I am able to watch HTML5 videos, I tried at the Quirksmode page: Quirksmode

Just to let you know: It works on Chrome with Widevine installed.

Raison d´etre: WIdevine needs to be installed, Adobe Primetime is not accepted by DAZN it seems. Afterwards, I tried to install widevine in Firefox manually, too, but it is not found in about:plugins. Do you have any idea/suggestions how I can find out the reason for it not being discovered?

Google has not supported WinXP/Vista since April 2016 as of Chrome version 50 and later so it is quite vulnerable now.

That's a good point, James, I will keep this in mind. Still, I am technically interested in the reason for firefox not listing the WIdevine plugin. Is there kind of a debugging option to follow the loading process while Firefox is started? Or any kind of log file that could point me in the right direction? The plugin is at the directory it is expected. I have read that I should deactivate and activate the checkbox "Play DRM content" in about:preferences#content again to trigger a refresh, but unfortunately this option is not in any of my firefox versions I have tried. Why?