Currently, when you migrate a (sub)wiki, the platform is not able to know which XAR it should install.
Actually, you should install:
- xwiki-enterprise-ui-common if you are upgrading a standard subwiki.
- xwiki-enterprise-ui-wiki if you are upgrading a workspace
But the platform will propose you xwiki-enterprise-ui-wiki in every case.
The idea is to create new module that the Distribution Wizard ask to know which XAR it should install.