Apparently "The majority of the content in the Original Avatar marketplace is external to Microsoft so they can’t do anything to change it or recreate it." So it would be up to the original creators to upgrade all the previous system avatar items to the new system, and even if they did it's...
The expansion pack for Battlefield™ 1, titled In the Name of the Tsar is currently free. It looks like it is for a limited time.
https://www.microsoft.com/en-gb/store/p/Battlefield-1-In-the-Name-of-the-Tsar/BQ0V41G2R0FP
TheGameAwards - Warframe - Free Broca Prominence Syandana and earn a special Twitch Drop
https://forums.warframe.com/topic/890113-celebrate-warframe-at-the-game-awards/
https://www.twitch.tv/thegameawards