DW fails to find the previous version of the workspacetemplate during an upgrade from 5.1.1 to 5.4

After upgrading the main wiki, DW proposed me to upgrade all subwikis.

I successfully proposed me the good UI to install for my workspace, but for "workspacetempate", it asked me if it is a new install or an upgrade.
After clicking on "this is an upgrade", it asked me to select the previous version in an empty select filter.

Environment: I used xwiki-manager-jetty-mysql-5.1.1 and a local build of xwiki-enterprise on the branch stable-5.4.x.

Then, if I click on "I don't know", it proposed to install XWiki Enterprise - UI - Wiki 5.4-SNAPSHOT (which is good).