Do I need to pay to upgrade my U2000 license?

Hello, friend.
According to your description, I don't think you need to buy license files again. But need to upgrade U2000, open the following link, enter the current version and target version, and download the upgrade file as prompted.
http://support.huawei.com/onlinetoolweb/umms/SearchActionEN

Hello Friend,

First, thank you for your response.

However, these steps have already been done, but the U2000 requested the updated license, so this process is not automatic. I will request the license update for my vendor.

Again, thank you!

Please send an email to license@huawei.com to explain the details, including the existing version, the target version, and the current license. Huawei engineers will reply the updated license to your email

email license@huawei.com