Talk:VOCALOID4/@comment-36309429-20180724023604/@comment-53539-20180724185716

Technically the only two engines which are hard to purchase are V1 and V2, you can still get V3.

But yes, each new engine release retires the previous one, but support remains for at least 6 years after retirement. At some point in the future V3 should be retired. so Akumi is right. However, Yamaha themselves tend to no longer sell the old engine and its only the 3rd party studios and devs who still sell the old engine. A grace period is normally given which allow producers to transfer into the new engine.