According to the latest Canon rumors, Canon is working on a new 24-70mm standard zoom lens with Image Stabilization feature. And this new lens will be EF 24-70mm f/2.8L IS USM lens.
The new F 24-70mm f/2.8L IS USM Lens will be more expensive than EF 24-70mm f/2.8L II USM ($100 off now), and it will not replace the current EF 24-70mm f/2.8L II USM.
At the same time, Nikon 24-70mm f/2.8 PF VR lens is rumored to come in the near future.
Take them with a grain of salt.
Read More: Canon Rumors