API STATUS: OPENED
Adding open tracking places an invisible image in the message. If the recipient loads the images from the message, Flowmailer registers this event. Rare exceptions notwithstanding, status Opened means that the recipient has -in all likelihood- opened the message. Please note that the absence of an Opened status does not mean the message has not been opened. Also, be aware that others with access to the message (such as administrators or certain automated processes) can theoretically trigger the Opened status.