The OnePlus twitter account has been focused on the 6 until now, but the first teaser tweet for the OnePlus 6T just came out. It features the hexagonal T logo of the upgraded model and almost certainly hints at the in-display fingerprint reader (which was already officially confirmed).
You can see Unlock The Future flash quickly, almost as a subliminal message. This isnt the first teaser, an ad even showed a glimpse of the phone.
OnePlus 6T. It’s coming. pic.twitter.com/Wrdt9sCdIs
OnePlus (@oneplus) September 28, 2018
The reply tweets below the teaser are about what you would expect. Someone is posting the 3D renders, others are complaining about the lack a 3.5mm jack and theres a lot of excitement mixed in as well.