Onboarding after a patch release is quite common in applications. It usually comes in the forms of tooltips or a "splash" screen when the user first opens the newly updated app.
However, if you do not want it to be too intrusive you can introduce it with a small dismissable bar at the top or bottom of the app e.g "Check out our new features here".
Particularly for your new menu action, a discreet notification icon over the new feature you introduced would also work.
Alternatively, if your app has a notification center you could add these onboarding messages in the notifications and let the user decide if they want to read about the new features or not.
Apart from the UI. There are other ways to inform users as well. Ensure your app-store screenshots are updated showing the new features and if you offer patch notes with every release ensure these new features are prominent and at the top of the release notes.