Apple Security Update2020-003

I've got serious problem with latest security update on my 13' MacBook Pro Retina (Early 2015). After update my Mac heats up and throttle as hell. I reinstalled Mac OS Sierra from scratch, changed thermal paste on CPU twice, nothing helped. I can have ~80 celsius on my CPU, when I'm only browsing the net on Safari. It's hard to use any powerful applications, because it can heat up to even ~100 celsius and above. Please help, what can I do? Did anyone had the same problem? Thank you in advance P.S. I can't upgrade my OS to newest version due to my health problems. So I have to stay with Mac OS Sierra.

OS and security updates now predominantly bring limitations and more and more nontransparent control and processes. Mojave 10.14.6 is maybe my last update on my 2018 MBP. I don't trust Apple no more. After more than 20 years working with Apple computers I feel that they deviated and we no longer can be safe like we were. Still infinitely better option than Windows or anything else but I feel something sinister. :(

Security Update 2020-001 was released on 28 Jan 20. More info: https://support.apple.com/en-us/HT210919

I've got serious problem with latest security update on my 13' MacBook Pro Retina (Early 2015). After update my Mac heats up and throttle as hell. I reinstalled Mac OS Sierra from scratch, changed thermal paste on CPU twice, nothing helped. I can have ~80 celsius on my CPU, when I'm only browsing the net on Safari. It's hard to use any powerful applications, because it can heat up to even ~100 celsius and above. Please help, what can I do? Did anyone had the same problem? Thank you in advance P.S. I can't upgrade my OS to newest version due to my health problems. So I have to stay with Mac OS Sierra.

Untangling Confusion:

The original "Security Update 2019-004 (High Sierra & Sierra)" contained a bug that affected Sleep mode on a few recent Mac models. Without explanation, Apple pulled the update for several days. Then, without explanation, Apple made the update available again with modifications that removed the Sleep bug.

If you have questions about whether you have the correct version installed, simply download and install this latest version. For details, please read:
"Apple has released High Sierra and Sierra Security Updates 2019-004 again"
https://eclecticlight.co/2019/07/29/apple-has-released-high-sierra-and-sierra-security-updates-2019-004-again/

If you have an older Mac, you are stuck on macOS 10.13.6. A number of people have had problems installing Security Update 2019-003 10.13.6, where on shutdown the Mac hangs at a black screen with just the cursor visible, requiring a hard reset that doesn't complete the installation. Rinse and repeat, but no success.

Quick solution to enable successful shutdown, but does not install the Update:
Delete the files that trigger the patch installation on shutdown
https://apple.stackexchange.com/questions/188842/black-screen-with-cursor-on-logout-in-yosemite

Solution to clear and reset a whole load of "stuff", and get the update installed:
https://davidsimpson.me/2018/11/14/fixing-failed-macox-10.13.6-security-update-2018-002/
The above works for update 2019-003 as well.

Works fine as usual

I have High Sierra 10.13.6. When I try to update with this download, it comes up with "ALERT. This update requires macOS version 10.12". Yet this download is supposed to be for my OS as well? I had previously tried to update in the App Store, but every time I restart my screen goes black apart from my mouse pointer which works perfectly, but nothing happens, it stalls. The only way to do anything is to power off and on again and it loads fine. But as soon as you do a restart, the same thing happens. Help!