MLB and the MLBPA did come to an agreement on the health and safety protocols for Spring Training and the regular season. The components for the regular season include keeping seven inning doubleheaders and starting extra innings with a runner on second base.
MLB/PA have a deal on health and safety protocols for spring training and the regular season.
— Joel Sherman (@Joelsherman1) February 9, 2021
At this point, there is nothing agreed to regarding the universal DH.
MLB has tried to attach the universal DH to expanding the number of teams in the postseason from 10-14.