IPhone in three sizes: 16, 32, and 64GB. The iPhone 5 and 5S were available in the same three sizes previously available to the iPhone 4S: 16, 32, and 64GB. The lower-cost iPhone 5C model was initially available in 16 and 32GB models; an 8GB model was added later. The iPhone 6 and 6S were available in three sizes at launch: 16, 64, and 128GB. The iPhone SE was available in 16 and 64GB variants at launch. When the iPhone 7 and 7 Plus were released, Apple changed the base model storage capacity from 16 to 32GB. Both the iPhone 7
IPhone on the O2 network in the United Kingdom, however, can buy the phone online and activate it via iTunes as with the previous model. Even where not required, vendors usually offer activation for the buyer's convenience. In the US, Apple has begun to offer free shipping on both the iPhone 3G and the iPhone 3GS (when available), reversing the in-store activation requirement. Best Buy and Walmart will also sell the iPhone. The iPhone's operating system is designed to only run software that has an Apple-approved cryptographic signature. This restriction can be overcome by "jailbreaking" the phone, which involves replacing the