Additionally, the resale value of Sprint-sold iPhones generally are the lowest of devices sold by the top four carriers in the country.[81] Means to unlock a GSM-capable iPhone exist, such as using a SIM interposer, but the device may not function fully or correctly on the desired network, and unlocking of the device had been a felony under the terms of the DMCA up until August 1, 2014 when Presid