According to an employee who works at a Sprint authorized retailer, he/she was able to order cases only for the 4.7-inch model. The website used by retailers to order the cases from Sprint indicated that the 5.5-inch cases and screen protectors would be "shipping soon." Popular cases like Lifeproof and Otterbox were not available for order.
Cases for both the 4.7-inch and 5.5-inch device have been popping up since April. There are even some cases for sale on Amazon and eBay for the upcoming device.
It is possible that these are simply placeholders for the upcoming device based on rumors that we've been hearing for months now. The iPhone 6 is expected to be announced on September 9, however Apple has yet to send out invitations.
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