The application is not compatible with any XWiki version below 10.6.1

It is the dependency on selectize.js implementation that brings this limitation. More precisely, the application's code relies on the changes from https://github.com/xwiki/xwiki-platform/commit/723d68366dcd966ea70db80c3f16c18ff13e72af#diff-f844229a4b06abe36e358548012ec0e1.