Document URL: 

https://docs.redhat.com/en/documentation/red_hat_satellite/6.18/html-single/upgrading_connected_red_hat_satellite_to_6.18/index#upgrading_capsule_server_upgrading-connected 
  
Section Number and Name: 

3.3. Upgrading Capsule Servers

Describe the issue: 

When customers don't have Satellite Infrastructure subscription in the manifest of the Satellite, the upgrade of the Capsules will get halted. 

Suggestions for improvement: 

It would be good to a have a note in the prerequisites to ensure that Satellite Infrastructure subscription is added to the manifest of the Satellite before the upgrade process for the Capsule is initiated.