According to the Canon rumor the telephoto lens is going to be announced with the EOS 7D Mark II on September 5, 2014. The upcoming lens is a replacement to the EF 100-400 f/4.5-5.6L IS.
EF 100-400 f/4.5-5.6L IS II will feature Rotating zoom ring and have New IS system. It’s weight will be Light in comparison to it’s predecessor. It will also feature 82mm filter thread. The price of the lens will be around $2399 USD.
Also see rumors about upcoming 7D Mark II Camera