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iMessage support was added with iOS 5 on October 12, 2011. The iPhone supported SMS, MMS and iMessage, while the iPad and iPod touch only supported iMessage. With iMessage, users could send text, picture messages and contacts over WiFi or 3G to other iOS 5 devices without using their carrier quota. In addition, a user could start their conversation on one device and continue on another. Messages also introduced typing indication, delivery and read receipts. With the introduction of Notification Center, new SMS, MMS or iMessages could be seen on the lock screen or by pulling down the Notification Center.