Why is high sierra marked as a update?

Hi Apple-users,

At this moment I'm using OS X Yosemite (10.10.5) and App Store is showing macOS High Sierra as an update, while it should be an upgrade.

As a matter of fact, that banner at the top marks it as an upgrade.

How can I get rid of that icon badge (which doesn't disappear)? I managed to get rid of the reminder-notifications, but it is a bit annoying.

Many thanks in advance!

Regards,

Gert J.