Logging.
I just updated to v16 and went through all my settings to check any new ones as you do.
I decided to look at logging and noticed a few new log types like spam checks etc, but putting them on detailed I don't get any logs written (No new log files) even though you would expect to have all spam check actions logged.
Same goes for a number of other log types which don't seem to have logfiles created.
Any ideas what I am doing wrong?