No kubernetes version to choose from

I have setup Rancher on 3 nodes using hyperkube v1.18.3, but when I created a new cluster kube000 it used only hyperkube:v1.17.2. There was no Kubernetes version to choose from in the Add Cluster form.

The Edit Cluster shows me version 1.17.2, but no newer version.

How comes?

Rancher is version 2.3.5

After upgrading Rancher the Kubernetes versions became selectable in the Edit Cluster form as expected. Problem solved.