Apple didn’t say when the final version of macOS Big Sur would officially launch, other than it would arrive in the fall/autumn. Based on previous years, however, we expect Apple to release macOS Big Sur around 30 September.
These Macs will be able to run Big Sur:
MacBook models from early 2015 or later
MacBook Air models from 2013 or later
MacBook Pro models from 2013 or later
Mac mini models from 2014 or later
iMac models from 2014 or later iMac Pro (all models)
Mac Pro models from 2013 or later