Calendar integration using .ics file attachments

iCalendar file is an industry-standard for sending calendar information via regular email as an attachment. These files have a .ics extension and contain basic information about the event.

PlusPlus supports calendar integration via iCalendar standard. If enabled, when a user enrolls in an event, PlusPlus sends an email confirming the enrollment with the details of that event. The email also comes with an iCalendar file attachment that Outlook and Gmail can parse and add to the user’s calendar as an invitation. (Gmail and Outlook handle .ics files differently; see details below.)

The advantage of this integration is that there is no need for any special integration as the entire handshake happens through the regular email and standard .ics file.

The disadvantage is that there is no connection back from the user’s calendar to the PlusPlus app. In other words, if the user declines or deletes the event in the calendar, there is no real way for the calendar to notify PlusPlus of that action. In case of an event being edited, we will send a new .ics file and users will need to manually delete the old event instance and add the new one.

Most popular office suites, including Google Suite and Microsoft Outlook 365, can parse .ics files. The method of the parsing is different, depending on whether the user employs Gmail or Outlook:


Gmail automatically recognizes the .ics attachment, and adds to the event to the user’s calendar as an invitation.

Currently deleted events will display a banner in the email message but will not get deleted from the user’s calendar.


Events do not get added automatically from the email. Instead, the user needs to click the attachment for the event to be pushed to calendar. (See more about this at

When a user is unenrolled from an event, the confirmation email will cross the event out in their calendar, but it is only removed if the attachment is clicked.

When an event with multiple timeslots is updated, the user needs to click the click the “+” button in the .ics attachment to update all the calendar entries.

However, when an event with multiple timeslots is deleted, only the first event of a multiple timeslot event will get deleted; the rest must be directly deleted by the user.

Admins can activate .ics attachments in event invitations by navigating to Menu > Settings > Calendar Settings, selecting the Include ICS file in event-related emails checkbox, and clicking Save.