How upgrade version8.1 Enterprise to version 9.0

[#1]

help !

How can I upgrade version 8.1 Enterprise to version 9.0

I input the license key and control number ,but unable to acquire valid license informaion .

why?

Thanks.

[dirk_konings]

Could you connect this : http://lef1.qliktech.com/

Do you have a maintenance contract (support + upgrade ) ?