VPN AlwaysOn and other changes in Xcode 12.2 Release Candidate build

From which version of devices the changes mentioned in https://developer.apple.com/documentation/devicemanagement/vpn/alwayson?changes=latest_major are present? Are they applicable to iOS and macOS platforms? Are they backward compatible? Would "VPN.AlwaysOn.AllowedCaptiveNetworkPlugin", "VPN.AlwaysOn.ServiceException" etc work on newer version of iOS and macOS devices?
VPN AlwaysOn and other changes in Xcode 12.2 Release Candidate build
 
 
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