OnePlus announced yesterday that it would discontinue the OnePlus 3T in global markets to make way for its 2017 flagship. However, the manufacturer has now stated that it will continue to sell the OnePlus 3T in India until "later this year."
OnePlus is currently rolling out a OxygenOS update to the beta channel that brings Android 7.1.1 to the OnePlus 3 and 3T. The beta release is now available to sideload, and the changes should make their way to the stable build shortly.
There's a huge difference between accepting pre-orders and being able to ship in volume as soon as someone tries to order. OnePlus has gotten pretty good at that first one, and now it's giving the second a try.