Apple today announced that iOS 15.1, iPadOS 151, watchOS 8.1, tvOS 15.1, macOS Monterey, and tvOS 15.1 will all be available as free software upgrades next week. Apple announced this information in a press release about the third-generation AirPods.
AirPods are compatible with Apple devices running iOS 15, iPadOS 15.1, watchOS 8.1, or macOS Monterey. All software updates will be free next week.
Update: Apple has updated its website to confirm macOS Monterey will release on Monday, October 25.