What it is
iCalendar encodes event identity, timing, participants, recurrence, and scheduling method in a text/calendar MIME part.
Why it matters
Clients use the machine-readable part to add, update, cancel, and respond to events. A human-readable date alone cannot synchronize calendars.
How to implement
Use one stable UID, increment SEQUENCE for material updates, emit the correct METHOD, include unambiguous time zones, and pair the part with readable message alternatives.
Common mistakes
- Creating a new UID for an update.
- Mixing local times with a missing time-zone definition.
- Sending cancellation text without a cancellation object.
Verification
Import the initial invitation, update, response, recurrence exception, and cancellation in multiple calendar clients. They must modify one event rather than create duplicates.