Photokina is a photographic trade show/fair which is run every September in Cologne Germany. It's one of the traditional reasons you will see a lot of announcements from camera manufacturers at this time, leading up to the event. It's also traditionally an event at which many manufacturers make their announcements and signifies the end of the camera announcements for the year.

With the way the internet is now operating usually there will be rumors or leaks before the show, so there are fewer surprises, but you never know what else may be announced.