Interview with Yosuke Yamane-san who lead the GH5s development
Here are some more tidbits:
– GH5 firmware to enhance performance might be developed if there is customer demand
– Both, the GH5 and GHS were developed at the same time and the intention was to release the GH5S first.
– By 2020, Panasonic is aiming to release an 8K GH camera.
GH5s at BHphoto, Adorama, Amazon, FocusCamera and Panasonic.