According to recently rumors on NR, Nikon will update their current AF-S NIKKOR 200-400mm f/4G ED VR II Lens with the new AF-S NIKKOR 200-400mm f/4E FL ED VR lens. This lens is targeted at sports photographers. It will have built-in 1.4x extenter as Canon version.
The optical quality of new AF-S NIKKOR 200-400mm f/4E FL ED VR lens will be extremely high and so will be the price. According to rumors, this lens will be announced in late 2017, and shipping date before 2018 FIFA World Cup that will take place in Russia from June 14th to July 15th, 2018.