Subscription calendars are powerful but have real limitations rooted in how the iCal standard and calendar apps work - worth understanding before you build a strategy around them.

Sync delay - the biggest practical limitation

Google Calendar typically syncs external subscription feeds every 12–24 hours. You can't push an instant update to all subscribers. If you make a last-minute change to an event time, some subscribers may not see it for up to a day.

Workaround: on paid plans, AddEvent supports push notifications that signal calendar apps to sync sooner. Subscribers can also manually refresh. For urgent changes, a separate email to your attendee list is the reliable fallback.

No read receipts or engagement data

You can see how many subscribers you have and export the list. You cannot see whether a specific subscriber opened or viewed a particular event, or whether they accepted the event into their calendar.

Subscriber-controlled unsubscribing

You can block or delete subscribers from your AddEvent dashboard, but you cannot control whether they see changes once they've unsubscribed within their own calendar app. The connection is ultimately managed by their calendar app.

iCal format constraints

Subscription calendars use the iCal (.ics) standard, which calendar apps have supported since the 1990s. This means:

• Event descriptions render as plain text - no HTML formatting, bold, or bullet points in the calendar entry itself
• Images don't embed in calendar events
• The display of event details is controlled by the attendee's calendar app, not AddEvent

Plan limits apply

Calendar subscriber counts count against your plan's monthly limit. The free Hobby plan allows 20 subscribers; Small Business 1,000; Professional 5,000.

These are characteristics of how subscription calendars work universally - they apply to every iCal-based subscription service, not just AddEvent.