Even though standards like USB-C and USB 3.2 are still gaining traction, the first devices with USB 4 still using the USB-C connector should arrive towards the end of 2020, according the USB Promoter Group.
While the standard is currently in a "0.7" release state, a variety of details are already known, Anandtech reported. The standard will for instance be based on Thunderbolt 3, but unlike current USB-C accessories operate at that standard's full 40 gigabits per second. Current USB-C cables are interoperable with Thunderbolt but can never go faster than 20 gigabits via USB 3.2, and more frequently run at 10 or even 5 gigabits.
The Promoter Group is further promising "multiple simultaneous data and display protocols," and backwards compatibility with USB 3.2, Thunderbolt 3, and USB 2.0.
An official USB 4 specification is anticipated this summer. The standard is considered to be such a radical change that the Promoter Group is contemplating new logos and branding.
Apple will likely want to adopt USB 4 as quickly as possible on Macs, given its rapid adoption of both Thunderbolt and USB-C in the past. Less certain is when the technology will migrate to the iPad Pro — which already has USB-C — and whether it will come at all to the iPhone. The company has so far resisted switching iPhones away from Lightning, even as USB-C becomes increasingly de facto on Android devices.