Is there any difference between USB-C and USB 3.1?
The new USB type C specification is version 1.0.
USB C replaces multiple type-B and type-A connectors and cables.
The USB 3.1 standard is backward compatible with USB 3.0 and USB 2.0.
The USB Type-C Specification 1.0 defines a new small reversible-plug connector for USB 3.1 devices. The type-C plug will be used at both host and device side, replacing multiple type-B and type-A connectors and cables with a future-proof standard similar to Apple Lightning and Thunderbolt.
Source USB 3.1