The official announcement for previous leaked FE 200-600mm f/5.6-6.3 G OSS Lens is expected next week sometime. Along with this super telephoto zoom lens, rumors said Sony will also announce a new super telephoto prime lens next week. The most likely to be announced lens could be FE 600mm f/4 GM OSS lens or FE 500mm f/4 GM OSS lens. In the past, there were already patent for these super telephoto prime lenses.
In the second half of 2019, Sony is going to announce the a9 II flagship full frame mirrorless camera, so these two new FE lenses will be great combo for Sony a9II. Stay tuned for more info.