diff --git a/pkg/api/common/versions.go b/pkg/api/common/versions.go
index 912359c9f9..16f825c221 100644
--- a/pkg/api/common/versions.go
+++ b/pkg/api/common/versions.go
@@ -232,7 +232,7 @@ func getAllKubernetesWindowsSupportedVersionsMap() map[string]bool {
 		"1.10.0-rc.1",
 		"1.11.0-alpha.1",
 		"1.11.0-alpha.2"} {
-		ret[version] = false
+		delete(ret, version)
 	}
 	return ret
 }