We're getting new information about the EOS 5D Mark IV quite slowly, but a lot of it I believe to be reliable.
The latest is about how the camera is going to launch. We've confirmed that the EOS 5D Mark IV will be announced in late August/early September in time for Photokina, which begins on September 20, 2016 and runs through to September 25, 2016. The ship date for the camera should quickly follow if everything goes to plan. This sort of launch would mimic the way the EOS 5D Mark III was launched and released. We think there's a good chance you're going to have the EOS 5D Mark IV in your hands some time in October, 2016, if not sooner.
If you're interested in the camera, start saving your pennies. We expect a launch price of about $3500 USD, which is identical to the EOS 5D Mark III at launch.
The only reliable specifications we've been told is that camera will shoot 4K, have built-in wifi and GPS and have some touchscreen functionality. A less reliable source has told us the camera will shoot to CFast, just like the EOS-1D X Mark II. We're sure the camera will have dual slots, but we don't know how the media will be configured.
We expect a lot of chatter around NAB this month in Las Vegas.