It is out. Ver 2.0 and I have downloaded and installed it

Also an update accompanying for PhotoFunStudio 9.5

This link
panasonic.jp/support/global/cs/dsc/download/fts/

I still have not "tested" but there appear to be several (lots actually) extra menu and function-button functions available, more than described in the note given (copy below) on the website.
i.e. (it's in slightly less unintelligible Japlish than usual)

[4K PHOTO] mode is added which records 4K video exclusively for capturing a frame to save as a photo.
Settings can be adjusted as below when entering this mode.
-Rec Format : MP4
-Rec Quality : 4K/30p/100Mbps
(System Frequency 59.94Hz)
4K/25p/100Mbps
(System Frequency 50.00Hz)
-Luminance Level:0-255
In addition to 16:9 aspect, 4:3/3:2/1:1 can be selected.
Exif information is embedded to the captured image from the 4K video.
Marking function is available enables marker setting on the designated point while recording video and users can jump to the markers when playing back the video to capture the frame they want.
Loop Recording function is added, with which the camera keeps on recording video while deleting the old footage automatically.
4K/23.98p/100Mbps mode is added in MP4 video recording.
The upper limit of the ISO sensitivity can be set in the menu of ISO sensitivity setting and emission amount of flash light can be adjusted in the menu of exposure compensation.
Focusing performance of 1-area AF in video recording is improved.
Tracking performance of tracking AF when used with the interchangeable lens H-FS14140 is improved.
Remote shooting via USB tethering is available by using PC software "USB Tether" supplied by Promote Systems.
* For more information on Promote Systems, please visit www.promotesystems.com/

One should also download and read the explanatory PDF link on the firmware page i.e.
eww.pavc.panasonic.co.jp/support/en/dsc/fts/win/GH4_V20_E...
This is written like an addenda to the Advance Operating Instructions.