Currently a minor upgrade from 16.1 to 16.2 requires an interim step where the source environment is updated to the latest 16.1 zstream before upgrading to 16.2. This takes a lot of time and operational resources, including hypervisor reboots which are especially costly to operations. We should be able to update from any 16.1 source zstream to the 16.2.latest without requiring the interim update process. We must implement the testing to validate that on an ongoing basis.
I think we should add a hard requirement of maintanance window and downtime while doing such a risky operation (it might affect dataplane). Or we should recommend to drain dataplane nodes and execute minor update in batches. Anyway, please make sure 16.1.x to 16.2.2 is tested for no dataplane interruptions, before accepting this one