It remains to be defined when the USB-C or Thunderbolt 3 connections will be replaced, both accessible through the same input on current equipment. But there is already talk of Intel's Thunderbolt 4 (and also USB 4), which is forcing manufacturers to deepen the minimum requirements of their equipment for their use, so that most systems are compatible.
The first two generations of Thunderbolt used miniDisplayPort, but in 2015, the third generation moved to the USB-C format, which seems to have had a greater consensus in the acceptance of users and manufacturers. Thunderbolt 4 will use the same input for current cables, USB-C, but also the same bandwidth of 40 Gbps per second, something that was met with disappointment by tech geeks.
However, the miminho is reserved for the transfer speed of the PCIe SSD storage systems, which will now double, from the current 16 GB per second to 32 GB, which makes it more practical and faster to pass heavy videos for editing. The goal is also for computers to be able to connect two 4K screens, or alternatively an 8K monitor. Even though it is currently possible to do it via Thunderbolt 3, the manufacturers do not give this guarantee, so Intel is registering it as a requirement for the next generation.
Regarding security, Intel will use its VT-d virtualization technology that protects against direct access to memory, the so-called DMA attacks. Experts say that the main operating systems already support this technology, which does not cause problems with adoption.
Another requirement that Intel is asking for PCs and laptops to have at least one of the inputs compatible with USB-C power charging, up to a maximum of 100 W. This also means that Thunderbolt and USB will continue hand in hand in the future, since the Thunderbolt 4 protocol will be compatible with USB 4, which has been postponed.
The fact that different generations of USB and Thunderbolt use the same USB-C connection can make it easier for users to understand on paper. Only in practice, the requirements are totally different, and one often looks at the entry and does not read the symbols or requirements, making incompatibilities a confusing one. See even what happens with USB-A-dependent equipment, with three generations on top, forcing you to pay attention to the type of cables you purchase for use.
For all intents and purposes, a flash symbol near a USB-C port means that it is compatible with Thunderbolt. As for a specific date, still early, but the promise that will support the next notebook processors based on the Tiger Lake architecture, probably later in the year.