How to add init variables for a constantly updating game

Hello! I have an rpg game that's constantly being updated - new side quests or new plots, for example. I understand that if I update the StoryInit with new variables, players already with saved games won't be able to access these new additions. What would you recommend I do so that players won't constantly have to start new games just to get the new updates?

Thank you! I am currently on Twine 2.0.11 and Sugarcube 2.12