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Browser header mystery

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I am running Windows 11 23H2, upgraded from Windows 10. I have just done a check with Steve Gibson's "ShieldsUp!!" and the browser header is stated as follows:-

Connection: keep-alive Content-Length: 31 Content-Type: application/x-www-form-urlencoded Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/png,image/svg+xml,*/*;q=0.8 Accept-Language: en-GB,en;q=0.5 Cookie: ppag=zuhygut2gvnnw; pcss=zuhygut2gvnnw; pico=dbfq5ltar45ex; tpag=zuhygut2gvnnw; tcss=zuhygut2gvnnw; tico=dbfq5ltar45ex Host: www.grc.com Referer: https://www.grc.com/x/ne.dll?rh1dkyd2 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:128.0) Gecko/20100101 Firefox/128.0 Origin: https://www.grc.com DNT: 1 Upgrade-Insecure-Requests: 1 Sec-Fetch-Dest: document Sec-Fetch-Mode: navigate Sec-Fetch-Site: same-origin Sec-Fetch-User: ?1 Sec-GPC: 1 Priority: u=0, i FirstParty: https://www.grc.com ThirdParty: https://www.grctech.com Secure: https://www.grc.com Nonsecure: http://www.grc.com Session: ac2uanrdjz2e

Notice that the user agent line identifies the OS as (Windows NT 10.0; Win64; x64; rv:128.0) Isn't this a bit odd? Is this a bug in Firefox?

Shouldn't the user agent information refer to Windows NT 11.0?

This installation of Windows 11 otherwise works very well.

I am running Windows 11 23H2, upgraded from Windows 10. I have just done a check with Steve Gibson's "ShieldsUp!!" and the browser header is stated as follows:- Connection: keep-alive Content-Length: 31 Content-Type: application/x-www-form-urlencoded Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/png,image/svg+xml,*/*;q=0.8 Accept-Language: en-GB,en;q=0.5 Cookie: ppag=zuhygut2gvnnw; pcss=zuhygut2gvnnw; pico=dbfq5ltar45ex; tpag=zuhygut2gvnnw; tcss=zuhygut2gvnnw; tico=dbfq5ltar45ex Host: www.grc.com Referer: https://www.grc.com/x/ne.dll?rh1dkyd2 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:128.0) Gecko/20100101 Firefox/128.0 Origin: https://www.grc.com DNT: 1 Upgrade-Insecure-Requests: 1 Sec-Fetch-Dest: document Sec-Fetch-Mode: navigate Sec-Fetch-Site: same-origin Sec-Fetch-User: ?1 Sec-GPC: 1 Priority: u=0, i FirstParty: https://www.grc.com ThirdParty: https://www.grctech.com Secure: https://www.grc.com Nonsecure: http://www.grc.com Session: ac2uanrdjz2e Notice that the user agent line identifies the OS as (Windows NT 10.0; Win64; x64; rv:128.0) Isn't this a bit odd? Is this a bug in Firefox? Shouldn't the user agent information refer to Windows NT 11.0? This installation of Windows 11 otherwise works very well.

All Replies (2)

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I have a hunch that Firefox stored the ID of the OS in use at the time of installing Firefox and that OS was Windows 10. If my hunch is correct, that means that Firefox is now oblivious of the change of OS to Windows 11 23H2.

I guess that this matters because the browser header tells the web site what OS the client is using. It matters especially if the website imposes restrictions to ensure that only up-to-date OS versions are allowed to access it. My online banking is with HSBC and it is very careful only to allow users of supported OSs to access online banking. That means that after October 2025 and the end of support of Windows 10, that will make a big problem for me because I anticipate HSBC blocking unsupported Windows 10 users.

Helpful?

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I have read that Windows 10 and Windows 11 use the same kernel. Does this explain away the problem?

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