When it comes to Cisco ACI APIC upgrades, there are three main paths to take: in-place, parallel, and staged. In-place upgrades are the most straightforward, and involve upgrading the APICs one at a time without interrupting service. This is the recommended approach for most deployments.
Staged upgrades are ideal when upgrading a large number of APICs, or when there are complex dependencies between APICs. This approach involves upgrading a small number of APICs at a time, and then gradually rolling out the changes to the rest of the deployment.
No matter which approach you take, it is important to have a plan in place before beginning the upgrade process. Make sure to test the upgrade process in a non-production environment first, and have a rollback plan in case of any unforeseen problems.
