Best Macos version?

ishu64 wrote:

Which macos version is best for macbook air 2017 ? As I am having problem with its battery backup on Macos Big sur so I am thinking of downgrading it.........so please tell me that which os version will be best for it.

You are best served by running the latest macOS 11.2.3 for features/security/compatibility

It never pays to get behind in the hardware or software.

My battery runtime is low

https://support.apple.com/en-us/HT204054#runtime

Batteries - Maximizing Performance - Apple

https://www.apple.com/batteries/maximizing-performance/

Determine battery cycle count for Mac notebooks

https://support.apple.com/en-us/HT201585

Rather than post a survey question, which is out of scope for community guidelines, why not better describe the issue you are having with the battery on your 2017 MacBook Air, as it relates to your installation of Big Sur?

What does "battery backup" mean? Are you having issues with battery life, or a battery that does not fully recharge? Are you using the Apple charger, or a third-party charger. Tell us more.

The "best" macOS version for any Mac would be the one that was designed specifically for that Mac, i.e., the one that shipped on that Mac.

However, newer OS versions may have better functionality (or worse depending on your use cases), and it will have better security once Apple stops updating the older OS.

As always, what is "best" depends on lots of personal opinion. Only you can decide for yourself which is "best."

macOS Catalina will be highly recommended