

You take it to the Apple Store and they just give you an other one. If you need to know the build number as well, click the version number to see it. The window that opens might look different from the example shown here, but it always includes the macOS name followed by its version number. If it gets bricked (which happened to a phone of mine before) I've never had a problem with Apple Care. From the Apple menu in the upper-left corner of your screen, choose About This Mac. I don't care about it getting bricked because it is still covered. On a machine that is still protected by Apple Care and is just a general computing device and all legit, internet, word processing, nothing that will mess with my outside of a bit of inconvenience I take updates after about a week if I don't hear about huge vulnerabilities. New OS bring some features and possibles but if a machine is working fine now and will cause headaches and lost time because of an upgraded OS that will not affect it's performance I will wit or leave it as is. On computer that is running legacy extensions or applications that are necessary to its function I wait to hear about updates or workaround and decide if perhaps this particular computer has reached EOL of if I need to replace a particular application in order to update.
BIG SUR VS CATALINA DRIVER
On a computer you need for work that isn't exposed as a server I always wait till at least two patch cycles and updated driver availability the same applies for an older computer running up to date software and no legacy extensions.

All my computers are running the latest version of Catalina but I am still waiting for some drivers. Personally I plan on waiting till probably after the new year at least. There are some pretty decent code and speed optimization offered by MacOS 11 but they are not life chancing. Nobody but you can make those decisions because only you know how you use your computer, what is on it and what devices are attached to it.
