If you are not familiar with the oc command, refer to OpenShift - Getting Started with the oc command.

Before issuing the oc version command, issue the oc login command. The oc get clusterversion command can be used to return the cluster version of OpenShift.

~]$ oc get clusterversion
NAME      VERSION   AVAILABLE   PROGRESSING   SINCE   STATUS
version   4.6.8     True        False         188d    Cluster version is 4.6.8

If OpenShift is being upgrade, PROGRESSING should be True and status should be "Working towards new version".

~]$ oc get clusterversion
NAME       VERSION    AVAILABLE    PROGRESSING    SINCE    STATUS
version    4.10.13    True         True           9m1s     Working towards 4.10.30: 97 of 773 done (12% complete)

The --output YAML or --output JSON options can be used to display more details.

~]$ oc get clusterversion --output yaml
apiVersion: v1
items:
- apiVersion: config.openshift.io/v1
  kind: ClusterVersion
  metadata:
    creationTimestamp: "2020-10-21T18:30:38Z"
    generation: 4
    managedFields:
    - apiVersion: config.openshift.io/v1
      fieldsType: FieldsV1
      fieldsV1:
        f:spec:
          .: {}
          f:clusterID: {}
          f:upstream: {}