With the Fusion 5.5.0 release, Support observed a situation where a client upgraded their Kubernetes version before running the upgrade with helm and this caused deprecated errors because the old version of the cluster was now using deprecated Kubernetes APIs. This caused the upgrade to fail to the targeted version 5.5.1-3.
Fusion 5.5.0 to 5.5.1-3, with Kubernetes AKS 1.22 to 1.23.12
This was resolved by exporting the application in the old environment, setting up a new Kubernetes cluster on Fusion 5.5.1-3, and importing the application. This is not a recommended route unless the major release is the same. It is also recommended to do Kubernetes upgrades after the upgrade to the cluster on an in-place upgrade.