Is the core OS of Big Sur still Catalina for older machines?

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Is the core OS of Big Sur still Catalina for older machines?

I recently installed MacOS Big Sur 11.4 on an iMac 27' late 2015 and on a MacBook Pro 15' of 2014. Accordingly, under "About This Mac" MacOS Big Sur version 11.4 is indicated.

However, after login on a Website I received from them a security email warning me about the recent login and listing my IP address, the browser used and the OS version which is... MacOS 10.15.7.

I have then tried with Safari, Firefox and Chrome also on deviceinfo.** and whatsmyos.***, in all cases I am told that I am using MacOs 10.15.7.

Is this normal? Is for older machines the core OS of Big Sur still Catalina? Can somebody using Big Sur confirm?

Thank you in advance

[Edited by Moderator]

Posted on May 30, 2021 8:07 AM

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Answer 1

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MrHoffman

Community+ 2024

Level 10

117,909 points

May 31, 2021 5:57 PM in response to SubAlpino

What you’re describing is normal and expected, and due to changes underway to Safari, Chrome, and other web browsers. These changes are intended to make individual tracking more difficult, and to encourage websites to use common and portable means (hints) for identifying browser features across different web browsers.

Here’s a write-up from Chrome:

https://www.bleepingcomputer.com/news/google/google-chrome-aims-to-make-browser-user-agents-obsolete/

https://groups.google.com/a/chromium.org/g/blink-dev/c/-2JIRNMWJ7s

Here’s what the websites are doing (this is a little outdated, but still correct)

https://developer.mozilla.org/en-US/docs/Web/HTTP/Browser_detection_using_the_user_agent

Where Apple is headed with Safari and WebKit:

https://webkit.org/tracking-prevention-policy/

I just checked an iPad running iPadOS 14.6 (current), and that’s showing as a Mac on a not-current version, and which is now the intended behavior:

Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_6) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/14.1.1 Safari/605.1.15

I’d expect to see more of this info disappearing, as the user agent string fades. This if the current crop of browser-related privacy changes stick.

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Answer 2

dialabrain

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122,711 points

May 30, 2021 8:10 AM in response to SubAlpino

SubAlpino wrote:

Is this normal? Is for older machines the core OS of Big Sur still Catalina? Can somebody using Big Sur confirm?

Thank you in advance

The sites in question haven't been updated to reflect/include macOS 11.

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Answer 3

SubAlpino Author

Level 1

8 points

May 30, 2021 12:39 PM in response to dialabrain

Not totally convinced about that. Too many other websites detect Mac OS 10.11.7.

Also, if I enter "javascript:alert(navigator.AppVersion) in the URL box in Chrome, the page returns:

"5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/90.0.4430.212 Safari/537.36"

So it seems that the browsers themselves indicate 10.15.7 as the operating system

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Answer 4

Barney-15E

Level 10

112,992 points

May 31, 2021 5:12 PM in response to SubAlpino

The User-Agent string that Safari on Big Sur sends out has the OS as 10_15_7.

The app sending the HTTP(S) Request can set whatever User-Agent string they want. There is nothing that requires they tell the truth.

It appears Apple hasn't bothered to update the User-Agent string.

You can customize it if you turn on the Develop menu.

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Answer 5

dialabrain

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122,711 points

May 30, 2021 1:01 PM in response to SubAlpino

I won't quibble. The sites in question list 10.15 both on my 5 Big Sur installs and my M1 MacBook Air.

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Answer 6

tbirdvet

Level 6

13,785 points

May 30, 2021 4:26 PM in response to SubAlpino

I see this quite often as well. Not to worry.

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Answer 7

dialabrain

Level 10

122,711 points

May 31, 2021 5:37 PM in response to Barney-15E

Safari & Chrome = Your OS is OS X 10.15.7

Firefox = Your OS is OS X 10.15

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Is the core OS of Big Sur still Catalina for older machines?

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