The phrase "next iteration" means the next step or version of something that is being worked on or improved. It refers to moving forward and making changes or adjustments to reach a better outcome.
With Dirt Rally, I thought that it would be another 2 - 3 years before next iteration in the franchise, but this surprise announcement shows how can not believe how Codemasters continue to be one the best racing game developpers in the world. (blog.us.playstation.com)