alter compatibility level I plan to change the compatibility level on the databases in an sql server 2016 sp1 instance from 100 to 130. When upgraded from sql 2008 to sql 2016 the compatibility level was changed from 80 to 100.
I also am in the planning stages of installing the SP2 and the latest cumulative update.
What is best practice for changing the compatibility level - before or after the SP2 and cumulative updates are installed?
What is best practice for changing the compatibility level - before or after the SP2 and cumulative updates are installed?

SQL Server 2016 SP1 is out-of-support so you should upgrade to supported service pack first.
Then the best practices for altering the database compatibility level are documented here: Change the Database Compatibility Level and use the Query Store