The first deadline is 40 games played by the end of May.
The proposal that passed at the draft looks like this for 2016:
June 5 - 40 games played
July 3 - 65
August 7 - 90
September 4 - 115
October 2 - 140
November 6 - 162
Each date is the first Sunday of each month. If that's too hard to remember, just aim for the last day of the month (like we've been doing) and be grateful there are still a few days grace before the deadline hits.