https://docs.openshift.com/container-platform/4.16/edge_computing/image_based_upgrade/cnf-understanding-image-based-upgrade.html

states "From OpenShift Container Platform 4.14.13, the Lifecycle Agent provides you with an alternative way to upgrade the platform version of a single-node OpenShift cluster. The image-based upgrade is faster than the standard upgrade method and allows you to directly upgrade from OpenShift Container Platform <4.y> to <4.y+2>, and <4.y.z> to <4.y.z+n>."

However, 4.14.z to 4.14.z+n updates are not supported for IBU due to a lack of QE testing for this use case.    

4.14.z >=4.14.13

100% as this is a documentation bug.

    1. Compare stated support (4.y.z -> 4.z+n for releases >=4.14.13) against the IBU test plan at: https://polarion.engineering.redhat.com/polarion/#/project/OSE/wiki/CNF/Image%20Based%20Upgrade%20Test%20Plan
    

4.14.z -> 4.14.z+n is not tested by QE.