You can view the changelog for the theme here:
https://forum.graphene-theme.com/graphene-theme/changelog/
If by “what is going top happen with my site” you mean “will something on my site break” there is really no way to know. The best solution is to update only one thing at a time, and give it a couple of days between updating different items. (I’ve seen a lot of people who wait and do all updates—WP core, theme, plugins—all at once, which makes it impossible to determine where a problem comes from.) Give it a couple of days between updating items, so that you and your visitors get a good feel for how it’s working. I usually update something once or twice a week.