Christian Langmayr Thanks for your question! The RSVP function isn't currently controllable on a per-event basis, but it is possible for us to fully disable it for your community, or disable it for specific categories. If you would like for us to apply this change, send your request to support@forumbee.com.
In regards to time zones, event date/times are always converted to your local time zone setting on your community profile. This is set based on your computer time zone setting that was detected on your first login into the community. To see what your time zone is set to in the community, go to Edit Profile > Account and scroll to the bottom of the page under "TimeZone". If you have changed your computer's timezone and would like update your community profile to match it, click "Reset to local" which will set it your computer's current time zone setting .
Enter the event date/time for when the event would occur in your local time. When a member views the event, they see it in their local time zone. The system does this conversion automatically. It's similar to if you were to schedule a meeting in Outlook or Google Calendar, all invitees see the meeting schedule in their local time.
Unfortunately there isn't an option to set the clock to 24hrs. I'll add this as a feature suggestion in our backlog.