Board Thread:Questions and Answers/@comment-24527167-20141219012348/@comment-32500188-20141219063901

To answer your two questions: Yes, to both... as long as you own a legit copy of the V3 editor, the preferential sale will be available to you to take advantage of while they're offering it. (... that is, if you are able to navigate your way through the purchasing process. I know there was some sort of info out there that guides users on how to sign up to the JPN VOCALOID Store, but I can't find it for the life of me. I do know, however, some folks just copy the link of the page, open a new tab/window and run that copied link through an online translator to get some sort of hint as to what the information asks.)

All of the required info to get the discount is asked when you have logged into your account, added the V4 version you would like to purchase to your cart, and "proceed to checkout". There will be an area that says this close to the bottom of the next screen, where you'd fill in your customer information:

VOCALOID™4 Editor 優待版（ダウンロード版）のシリアルコード''' ※「VOCALOID™3 Editor」のシリアルコードを入力してください. '''

... That's where you would enter your V3 serial code, and it should recalculate how much you owe upon completing the rest of the required info and proceeding to the final steps of checking out. (Be sure to insert dashes between each 4-character sections of the code, though.)

(And just in case there are others out there who are curious: Keep in mind, the only way you'll be able to get the upgrade this way is via download... the Japanese VOCALOID store does not do international orders for physical copies, so if you were hoping to get one that way, that's going to have to be put off until you can either find it for a decent price on Amazon or Ebay, or wait until they update the English store and make it available there.)

If I find that page I was thinking about earlier, I'll come back and add a link to it... it had screenshots and everything, but I just can't remember the link. :-(