After migrating calendar items into Office 365 or Exchange it could happen that users will receive appointment pop-up reminders from the past.
This is normal behavior and happens when data is extracted and ingested into a target. The remainder, and whether it has fired or not, is part of the original message.
To prevent this behavior a new feature has been added to Archive Shuttle. This feature involves changing the message slightly to remove this reminder property.
To activate the change, go to the Office 365 Module tab on the System Configuration screen and select the “Disable reminders for appointments in the past Disables the Outlook reminder for an appointment that is in the past.” setting.
Any new data which is ingested will then have the reminder properties removed.