So they are supporting three generations of android version, so if a phone comes out on 8, that means it will receive major upgrades to 10, so that's 3 years th

So they are supporting three generations of android version, so if a phone comes out on 8, that means it will receive major upgrades to 10, so that's 3 years there and then Google seem to support 3 more years of security of 10 after it comes out. I'm aware android 8 is old now, just using it as an example.