USB 3.1, the existing Type-C format, tops out at 10Gbps.
Unlike micro and miniUSB, however, USB-C has been created to replace both ends of the cable.
The USB 3.0 Promoter Group's membership includes Microsoft, Intel, Apple, HP and Texas Instruments.
The existing USB 3.1 can transfer data at up to 10 gigabits per second using two lanes (5Gbps per lane), but the new USB 3.2 tech aims to double that to 20Gbps, or 2GB/sec, by allowing for 10Gbps per lane. However, what you won't require is a new cable.
Note, too, that this update applies only to USB-C, which is essentially a connector type. Or as the USB 3.0 Promoters Group says, "for users to obtain the full benefit of this performance increase, a new USB 3.2 host must be used with a new USB 3.2 device and the appropriate certified USB Type-C cable". That being said, it is a bit surprising to see that USB 3.2 is limited to using only two of the four SuperSpeed USB lanes available in the USB Type-C connector, and we may still see further improvements in the future to enable the usage of the remaining lanes.
USB-C can carry data across numerous connections such as Apple's Thunderbolt, Displayport, HDMI, and, of course, USB 3.1 - which is now the official data transfer standard for USB-C. However, it's likely to be a while longer before new devices designed around the USB 3.2 specification come to market. Thunderbolt 3 is already dramatically faster than stock USB-C, and offers 40 Gbps of bandwidth. However, all of your devices (for example, a notebook and an external SSD) will have to comply with the USB 3.2 spec for you to realize those speed gains. But now, using the wrong hardware can prevent a cable from reaching the specified data rates, or transferring the correct amount of power.
Changes have been made the hub specification to streamline the transitioning process between single-lane and multi-lane operation when different types of devices are connected to a hub. It is in its final draft review phase, with a planned formal release in time for the USB Developer Days North America event, 26-27th September 2017.