There is a free tool to help with migrations from OpenShift 3.x to 4.x - https://access.redhat.com/documentation/en-us/openshift_container_platform/4.2/html/mig

There is a free tool to help with migrations from OpenShift 3.x to 4.x - https://access.redhat.com/documentation/en-us/openshift_container_platform/4.2/html/migration/index?extIdCarryOver=true&sc_cid=701f2000000u72fAAA https://access.redhat.com/documentation/en-us/openshift_cont... It's not a rolling upgrade, but it allows you to move the apps, PVs, policies in as granular a manner as you wish.