Hey guys,
RapidWeaver 7.3 will have a way for developers to offer theme updates via sparkle. Theme updates in 7.3 work exactly the same way as plugin updates have always done.
Basic documentation on how to implement it can be found here:
https://realmacsoftware.kayako.com/article/82-7-3-adds-in-app-theme-updating
We hope to have a beta of 7.3 on the developer forum shortly.
Cheers
Dan