New Rules For 2021

There are some rule changes coming in 2021 and the document has come out earlier than expected. Some key changes to note:
1. No more lets. A serve that hits the tape and lands in the correct service box is now live and must be played. 
2. Drop serves allowed. Serves may be hit after the ball bounces and with no restrictions on the nature of the swing.
3. Asking about positions. Serving teams can now ask both whether they are the correct server and in correct position.
See the whole change document here.