The 2016 rules are at
https://www.cqww-vhf.com/2016_cq_ww_vhf_..._rules.pdf but no link to any 2017 rules. Probably safe to assume they won't be much different.
I guess it depends on who has nothing happening on (corrected dates) :
Begins: 1800 UTC Saturday, July 15, 2017
Ends: 2100 UTC Sunday, July 16, 2017
The timing might be a bit out for VK and ZL based on daylight hours on this part of the globe, but would still give some suitable timing on the Sunday morning, starting very early our time and giving us all day etc.
Note that the Aussie (WIA) Winter VHF/UHF Field Day is on 24/25 June 2017 so no conflict there and it could be used as a warm-up for the CQWW VHF event.
Any takers ??