Cannot find how to upgrade to higher version

HI Guys,

I click the button '* You can upgrade your version here.' from your HIKShop Essential page. I got the error message below,
Not Found
The requested URL /extensions/upgrade-my-version.html was not found on this server.
Apache/2.2.16 (Debian) Server at v3.hikashop.com Port 80

Will you please advise how much I need to pay if I have purchased HIKaShop Essential previously and plan to upgrade to Business version? DO I just pay the difference?
(2) If I upgrade to business version, all the setting in lower version will remain unchanged or I have to set everything again?
Please advise,

thanks,

jon

Hi,
1. Reading that documentation will probably help you.
2. If you want to upgrade to the business version you should do it through this page .