We have the email list of everyone who bought the game on itch so when updates that would have been posted on itch are released, they will be made available. We are still working on exactly how they will be distributed. When a steam version is released existing purchasers will get the option of getting a steam key.
Patreon is only for those who want to participate in the Subscriber only chat on discord(where I’m actively discussing a lot of the changes in real time) or if you want access to alpha and beta builds of the new version. The first release of the new version that Itch purchasers will get is the new version that has all of Flares content only, which will eventually be the demo version as the rest of the content gets added.
TL;DR: We will have ways for you to get the new one if you purchased it on itch.