User blog comment:Tigressnayi/Vocaloid 4 Editor???/@comment-6433273-20171218224741

You can buy it on amazon (US), [https://www.amazon.co.jp/YAMAHA-%E3%83%A4%E3%83%9E%E3%83%8F-%E3%83%9C%E3%83%BC%E3%82%AB%E3%83%AD%E3%82%A4%E3%83%89%E3%82%A8%E3%83%87%E3%82%A3%E3%82%BF%E3%83%BC-VOCALOID4-Editor/dp/B00QC09CVA/ref=sr_1_1?ie=UTF8&qid=1513636134&sr=8-1&keywords=vocaloid4 Japan, UK, Canada, France, Mexico) Character Planet (Korea; will ship internationally) and digitaly on the VOCALOID shop

You may also wanna check the Where to buy VOCALOIDs thread on VO (Vocaloid Otaku).