OnePlus has already announced that it will release a 5G-compatible device in 2019, but in a new statement, the company says that it will not be the successor to the OnePlus 6T.
The reason for this is likely cost, as the first generation of 5G support may add cost to the fairly low priced OnePlus devices. However, the company may be releasing its first device outside of the main lineup since the OnePlus X. This may be a higher priced device with 5G and maybe a few other goodies.
There’s no info on the upcoming 5G device so it’s all speculation until then. We’ll have to wait for an official OnePlus announcement come 2019.