There was an email in mid December 2016, another one at the beginning of March 2017, and if I remember correctly, one even before that. I'm not even a Pro user.
Confirming, I got mail on Dec 16 and Mar 03 notifying me of this. (Pro User, they renewed my account automatically on Dec 01, which annoyed me somewhat... "Here' we're taken your payment, but failed to mention to you we were announcing in two weeks the removal of the most useful bit to you from the service you're paying for! Have a nice day!"