Originally we had linked to this tweet but it has since been deleted. As you can see, Panasonic New Zealand confirmed that the V-Log update is coming out in October of 2015. Given the competition in the 4K sector recently, we doubt Panasonic is going to charge for this update like they were previously considering.
The GH4 is a good camera that you can produce good 4K video with. It’s not perfect, and there are better options, but it remains a solid value and an acceptable choice.