Amazing news, even if I will never own a 8K display this is good news for every 8K fan, VESA is working on the next generation of DisplayPort. While v1.3 and 1.4 only got minor changes which overall mean more data bandwidth, the new standard gets more features.
VESA plans to publish this update within the next 18 months.
Overall you need to wait DP 1.4 is still pretty rare right now and the first UHD monitors with the standard are expected this year, so there will be no 1.5. until next or 2020 for the mainstream user available.
The new generation also supports High Bit Rate3 (HBR), Display Stream Compression (DSC) [same like HDMI 2.1] among the higher bandwidth rates. The new cable gets the DP8K Certified DisplayPort cables print on it which makes it easier to verify the cable. The official cables will be sold by ELKA International, Hotron Precision Electronic Industrial, Dezhou HongJu Communication Technology, Ji-Haw Industrial & Ningbo Prime Electronic.
The cable will not be ready for 120 Hz 8K without the compression (DSC). Personally I will skip this and might wait for the next generation, I’m really happy with my 4K TV right now and I have no plans or needs to change this, besides it wouldn’t make sense because I sit 3 meters behind the screen and overall there would be any noticeable benefit from this distance and view angle.
VESA Strengthens 8K Video Resolution Ecosystem with Market-ready DP8K Certified DisplayPort Cables (vesa.org)