Yamaha has officially moved on to Vocaloid 6 (which features AI tuning). However, you can still purchase and download Vocaloid 5 from authorized resellers like:
Vocaloid 5 is like a classic analog synth. It doesn’t have all the smart features of the new gear, but it has a character that many of us still crave. Plus, for anyone sitting on a collection of V4 voicebanks, V5 is the last great editor that treats them like first-class citizens. vocaloid 5 download
When you download Vocaloid 5, you get:
Note: You cannot buy V5 directly from the official Vocaloid website anymore—they will redirect you to V6. Yamaha has officially moved on to Vocaloid 6
You're looking to download Vocaloid 5!