New operator.yaml has following variables defined:

        # X86_64 / AMD64 / default

        - name: RELATED_IMAGE_ActiveMQ_Artemis_Broker_Init_781

          value: registry-proxy.engineering.redhat.com/rh-osbs/amq-broker-7-amq-broker-78-init-rhel8:0.3-3

        - name: RELATED_IMAGE_ActiveMQ_Artemis_Broker_Kubernetes_781

          value: registry-proxy.engineering.redhat.com/rh-osbs/amq-broker-7-amq-broker-78-openshift-rhel8:7.8-3

operator.yaml from previous releases doesn't. Simply replacing image in old (7.8.0) operator.yaml with current image creates operator instance which appears fine, however is unable to spawn broker pods, with following error message:

create Pod ex-aao-ss-0 in StatefulSet 
ex-aao-ss failed error: Pod "ex-aao-ss-0" is invalid: 
[spec.containers[0].image: Required value, spec.initContainers[0].image:
 Required value]

That error message is unobvious and is buried deep in Events log of openshift. On the surface, for the end user problem looks like the operator simply didn't create any pods.

Proposal here is to include warning about unobvious incompatibility of modern operator with older operator.yaml

This incompatibility is introduced the first time, i.e. prior to current release re-using old operator.yaml either was immediately visible (operator doesn't spawn at all) or was working fine (operator works as-expected).