OnePlus has been pretty good about rolling out consistent software updates to its 2016 and 2017 devices, and that's set to continue.
That's all part of the plan, according to OnePlus, as the company is treating the 5T as an extension — as essentially the same phone — as the OnePlus 5. From a software perspective, despite minor differences and a few additional features in the newer model, they are identical.
Stable Oreo builds won't arrive until 2018.
With the OnePlus 3 and 3T currently testing Oreo as part of an open beta program, OnePlus plans to add the 5 and 5T to the same program before the end of the year. It specifically claims "late December" as the time frame.
Then, a few weeks later, the OnePlus 3 and 3T will receive final versions of Oreo, since they're a fair bit ahead in terms of development. Finally, the OnePlus 5 and 5T will get upgraded to stable versions of Oreo in "early 2018."
All told, OnePlus is confident that its 2016 and 2017 lineups will receive Android Oreo far before most other flagships, and that's good news for current and prospective owners. Even if it's a bit disappointing to wait until the new year for the stable Oreo build on the latest phones.