It's due to a policy, every Samsung phone released before 2022 receives 3 years of major OS update, including the A71, or any Samsung phone released in 2022 or newer will get 4 years of major OS update, excluding only the A23 and older, and ofc the A1x witch still get only 3 years, and the A0x will get 2, that's how it works, for the S series, the s24 lineup will get 6(or 7 idk exactly) years of major OS update while the S23 lineup will get 4 (or maybe they will expand it to 5 years) of major OS update
So we get to the conclusion, any A series phone that is released before 2022 will get 3 years (and won't be supported anymore) and the newly released A series (2022 and 23 and 24) will get 4 years of update, except the 2022 A23 and the A1x (doesn't matter what year) and the A0x will get 2
