By there were only ever four sockets, I meant in practical terms, not theoretically. Also, Samsung (and a very small number of other androids) had micro USB 3 f

By there were only ever four sockets, I meant in practical terms, not theoretically. Also, Samsung (and a very small number of other androids) had micro USB 3 for a year or two, but it worked with normal micro USB cables and they went back to micro USB shortly afterwards.