I am currently trying to use Google’s email markups to automatically add flight, event and hotel reservations to Google Calendar by sending the corresponding schema.org schemas via email.
Creating reservations and adding them to Google Calendar works perfectly fine for me using the App Script Quickstart method.
Unfortunately, updating and cancelling reservations does not seem to work for me. When trying to update a reservation, a new calendar event is created but the old one remains. For cancellation of the events I have tried both "reservationStatus" = "http://schema.org/Cancelled" and "reservationStatus" = "http://schema.org/ReservationCancelled" as stated in the schema.org dokumentation. None of them removed the events from the calendar.
According to another StackOverflow question "Google has confirmed via eMail that cancelling events and removing duplicate events after a reschedule was removed as a feature in December" 2019 but I have nor found any offical statement from Google regarding the deprecation of this feature.
Another question form the Google community page from 2020 states that cancelling events was still possible.
Does anyone have more specific information? It would be nice to get a clear statement from someone at Google.