@james.kleeh I'm aware. By your response I assume: You cannot have a Grails 4 service, with a Grails 3 plugin, where the Grails 3 plugin is included in the build via the settings.gradle. If that's true, it's fine and I'll disregard any attempt to make that work, but I was wondering if there is any workaround (acknowledging that I can't upgrade the Grails 3 plugin yet).