A. 1. Check for updates: Ensure you are using the latest version of the app, as these features may have been added in a recent update. 2. Use alternative methods: If the app does not support RSVP, consider using email or other communication methods to confirm attendance with event organizers.

B. 3. Provide feedback: While not contacting developers, consider discussing this with peers or on forums to see if others have found workarounds.