Windows XP and Vista users are being served 43.0.1 on mozilla.org intentionally due to 43.0.2 and newer installers being signed with a SHA-256 certificate.

If you have Vista SP2 with KB2763674 update then you can download 43.0.4 from http://archive.mozilla.org/pub/firefox/releases/43.0.4/win32/ or install the 43.0.1 and update to 43.0.4 route.

They started doing this for Vista users on Jan 6th,

I do have win vista sp2 but I have no idea of that kb2763674 is installed. When I followed that link I got microsoft site not able to understand what I was looking for.

Your archive link only gives me a list of directories and I have no idea what to do there.

I am able to get the firefox 43.0.4 on my win 10 machine.

Rosaliy Lynne said

I do have win vista sp2 but I have no idea of that kb2763674 is installed. When I followed that link I got microsoft site not able to understand what I was looking for.

Hi Rosaliy Lynne:

KB2763674 was released on 08-Jan-2013 and automatically installed on my Vista SP2 by Windows Update during the Patch Tuesday updates of January 2013. From the Start button, go to Windows Update | View Update History and look for KB2763674 in your list of installed updates as shown in my image in the thread Can't Download Offline FF v43.0.4 Installer with Vista - Get v43.0.1 Instead .

32-bit Vista Home Premium SP2 * Firefox v43.0.4 * NIS (2014) v21.7.0.11

no way to be sure - my update history only goes to 05-18-2013 but I can presume not since when I go to the firefox update from the vista machine I still can only get 43.0.1.

I'll have to check the microsoft website and see if that update is still available.

went to microsoft and downloaded the update for that but when I ran it - I got the message that it does not apply to my system. Looks like I am sol on that but I can still correctly download updates on my win 10 laptop. the question that arises though is this - will future firefox upgrades continue to work on vista machines? (and my still functional xp desktop machine)

Rosaliy Lynne said

no way to be sure - my update history only goes to 05-18-2013 but I can presume not since when I go to the firefox update from the vista machine I still can only get 43.0.1.

Hi Rosaliy Lynne:

It doesn't matter if you have the KB2763674 update installed on your Vista SP2 machine or not - all Vista users are currently being redirected to an old v43.0.1 (SHA-1 signed) offline Firefox installer when they visit the download page at https://www.mozilla.org/en-US/firefox/all/ regardless of whether their Vista OS is fully patched or not. This is because the browser user-agent on that download page that automatically detects your Windows OS and then recommends the appropriate installer can only detect if you have Vista installed, but it cannot detect if you have updated to the latest SP2 service pack and installed KB2763674. Mozilla has decided to assume a "worst case scenario" and redirect all Vista (and XP) users to the old v43.0.1 installer just in case their OS is out-of-date and can't run the latest available v43.0.4 (SHA-256 signed) offline Firefox installer.

...went to microsoft and downloaded the update for that but when I ran it - I got the message that it does not apply to my system.

I don't' know why your Windows Update history only goes back to 18-May-2013, but you can also go to Start button | Control Panel | Programs and Features | View Installed Updates and then search for KB2763674 to see if it's listed there (see attached image). If the Microsoft Download Center reports that KB2763674 does not apply to your system then the update might already be installed, or you might have clicked on the wrong download link from https://support.microsoft.com/en-us/kb/2763674. If you have 32-bit (x86-based) Vista SP2 the correct download link is https://www.microsoft.com/en-us/download/details.aspx?id=36296, while 64-bit (x64-based) Vista SP2 users should download KB2763674 from https://www.microsoft.com/en-us/download/details.aspx?id=36253.

32-bit Vista Home Premium SP2 * Firefox v43.0.4 * NIS (2014) v21.7.0.11

Thanks for that last direction. I was able to determine that the correct update is installed. I also tried using internet explorer, as opposed to my default firefox, and I got the same results with IE.

I have no clue how to fix this at this point but, I can still download the updates directly from my win 10 laptop so I will do it that way.

Firefox did update on the vista machine to 43.0.4 and it runs - I just can't download anything past 43.0.1 on the vista unit. Oh well - thanks for the help even though it did not solve the problem.