Here are the Nikon D6 updated/rumored specifications:
2oMP sensor, not 24MP as previous reported (still not 100% sure)
14 fps in normal shutter mode (the D5 could do 12 fps)
Improved/better AF system but probably with the same number of AF points
The Nikon D6 AF improvements are crucial and comparable to the Sony A9II
The D6 built-in sensor stabilization (IBIS) will be an improved version from the Nikon Z system
The D6 will have more features and customization options for various aspects of the camera and settings
Companion applications will also see improvements but they will most likely launch after the camera release
The D6 will definitely not be a “hybrid” camera, but rather a DSLR with some mirrorless features (better video, IBIS, silent shooting for example)
4K 60 video
Improved dynamic range
Advanced video features with RAW recording (not sure if external or internal)
Longer manual exposure times (like in the Nikon D810A): from 1/8000 – 120 seconds (up from 30 seconds)
Dual CFExpress memory card slots
.76-78x 100% viewfinder
New Expeed dual processors
Built-in Wi-Fi
3.2 million dots touchscreen
Improved silent shooting modes
Official announcement expected in mid-February (around February 12, 2020 ±1-2 days)