Currently, five different USB standards are used: USB 1.0, USB 1.1, USB 2.0, USB 3.0 and USB 3.1. USB 3.1 was released in 2016 and doubled the speed of 3.0. It optionally uses a different connector called USB Type-C, which is reversible (meaning you can plug it in both ways). USB 1.0 is now rarely used.