Honestly, just like Ring and Lui, the majority of the fanbase doesn't really see CV04 happening any time soon. We do know, though, that this is going to happen. We just don't know when. Unless they change their plans, we're getting a CV04.
Basically what dontmindmeyo said, we don't know when but it's assumed it will happen.
I'm assuming they were planning to release it much earlier but then with the popularity a.k.a money Miku brought they decided why mess that up with a potential flop CV04 could end up being and just decided to ride on Miku's popularity for as long as it would last. My best guess is that there will be もっと見る announcements after they finish Luka's and the Kagamine's アップデート to V3, basically whenever they finish doing whatever they could possibly do to their current voicebanks they would start talk about CV04 to keep things fresh. But in all honesty no one really knows but I highly doubt a company that received as much success as Crypton did, would just stop making new products.
