Apparently there are firmware updates for the new range of Panasonic camcorders.

HC-X1500, HC-X2000 : v1.2

1. HEVC LongGOP 100M 4K 59.94p / 50p recording mode has been added.
2. Added "White Clip" function and "Knee Off" setting.
3. Fixed a bug that "Super Gain +" does not work when returning to shooting mode from thumbnail display when "Super Gain +" is set .
4. Added support for RTMP streaming services "Azure Media Services" and "Twitch".
Fixed other minor bugs.

CX10 : v1.2

1. P2HD AVC-Intra 100/50 format recording are supported.
2. P2HD AVC-LongG12 format recording is supported.
3. HEVC LongGOP 100M 4K 59.94p/50p format recording are supported.
4. "White Clip" function and "Knee Off" setting are added.
5. When returning to shooting mode from thumbnail display when "Super Gain+" is set, "Super Gain+" does not work. This bug has been fixed.
6. RTMP streaming service "Azure Media Services" and "Twitch" have been supported.
Several minor bugs have been fixed.

There is also an updated manual to download.