They care what version of the CO is present. You can run an ‘update model object’ job against your blpackage to update the COs in the blpackage to the latest to match what’s on the targets.
What about environments with mixed agents? This seems very backwards for some reason. It's unrealistic to expect a large environment to be able to upgrade every agent at the same time (in fact, I can assure you it is impossible).
so - if you do the umo, does that resolve the issue ? (maybe make a copy of the object, run the umo on that and test ?)
i'd agree w/ you. the COs should be backwards compatible and generally everything else w/ the agent is.
can you post the actual bldeploy log w/ the error ?