The OnePlus 3 was a marked improvement over the company's "2016 Flagship killer" OnePlus 2. OnePlus is focused on the spec sheet, with the OP3 packing a Snapdragon 820 and 6GB of RAM. The company is now rumored to be working on a faster version of the device called the OnePlus 3T. According to @evleaks, it'll cost around $80 more.

The OnePlus 3T has been rumored for a couple weeks as a device that's very similar to the current OnePlus 3, but moves to the newer Snapdragon 821 SoC. That's the chip powering Google's Pixel phones. It's not clear what other specs might get a boost, but there had better be more than a slightly faster ARM chip if the price really is $80 higher. The OP3 is already $399, so if @evleaks is right we're looking at $479 or so.

The display might be a place to make some improvements—the 1080p AMOLED on this phone is just okay, and OP has had issues getting enough AMOLED panels lately. This might be a chance to jump to a higher resolution LCD that's easier to get in sufficient quantities.

A device with the model number A3010 was recently passed through Chinese regulators, which could be the OnePlus 3T. There's no launch time frame available, but it could be announced any time now.