Canon Rumors is reporting they have confirmed the new Canon 5D Mark IV will be released in late August or early September. This would be in time for Photokina which runs 20–25 September.
If everything goes as expected, the ship date would quickly follow the launch to get the cameras to customers in October, the same way the 5D Mark III was released.
Specs wise, 4K is an obvious addition, built-in Wi-Fi and GPS along with some touchscreen functionality. There are unconfirmed—less reliable—reports the camera will also shoot to CFast, the same as the EOS-1D X Mark II.
The rumoured price is US$3,500, exactly the same as the Mark III at its launch. The name is not set in stone either with speculation it will be called the 5DX not the 5D Mark IV.