Next dec 31st means 2025 right? So 10 status night to get in 1.5 years.Generally the validity of Accor plus is 1yr from the date of activation. Status level silver gold etc it’s based on calendar year. So if u buy now using hdfc offer ur Accor plus will be active till next July.
For status if u have no activity till dec 31sr other than 20nights which u got credited u would be silver till next dec 31st