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Important information to be included in the Attendee Template: Please add the below image tag (below link) in the Template, to generate a unique QR Code for each Attendee to be included in the Email. The QR Code can be scanned to Check-In/Out Attendees for an Event.

<img src="{!vfs__V4S_Attendee__c.Id}" alt="Logo"/><br><br>

The QR code is a combination of Salesforce Event ID and Salesforce Contact ID. The QR code changes for each Event, so if there are multiple events and multiple templates to be sent to Attendees. Please include the Image tag in all the templates which automatically combines the Event ID with Contact ID in the QR Code.