YES, the official 2021 Rulebook will become effective on January 25, 2021. One of the biggest changes is the Service Let. All in all there will be 125 changes to the official rules.
Service Lets have been removed. It is noted that out of habit, both referees and players may sometimes habitually call a service let. If any player stops play because of a service let being called, that player/team will have committed a fault per rule 7.I.
What is a Service Let? A serve is called a let when the ball hits the net cord but still lands in the service court (your opponent’s receiving rectangle). Such a serve is not considered a fault and the server may repeat the service attempt. A ball that hits the net cord but lands outside the service box is still a fault.
So with a Service Let being removed from the official rules for 2021, that means when the serve hits the net and lands in the receiver’s court, the ball will be in-play, and the server will not re-do a serve.