Betsy writes, on crazypickleballlady.com:
Updated 2019 USAPA/IFP Rulebook
USAPA and the International Federation of Pickleball (IFP) have published a new update to the Official Tournament Rulebook. It is available for free online at this URL address: https://www.usapa.org/ifp-official-rules/ Look for the book cover “2019 Official Tournament Rulebook.” These rules will go into effect February 15, 2019.
The new rule book makes no major changes in the rules, but it does make small changes to about 15 rules that can cause confusion in tournament matches. On the website, just below 2019 rule book image (at the above link), you will see “2019 Rule Revisions“. Click the red text that says “Click here to view.” This will give you a pdf file detailing the rule changes/clarifications.