Hi All, another Grails 4 + older plugin question here (apologies if this has been asked before but I am unable to find an answer so far). I have a Grails 4 Service, and I would like to utilise a Grails 3 Plugin (3.3.8) that builds with my app via an include in settings.gradle. My settings.gradle (example):

rootProject.name = 'abc-service'
File abcFolder = new File("../abc-plugin")
if (statusFolder.exists()) {
    includeBuild "../abc-plugin"
}

I cannot upgrade the plugin just yet as it is used by other Grails 3 services. I cannot build my Grails 3 plugin with my Grails 4 service with Gradle 5, as it fails due to use of a deprecated / removed method 'getClassesDir' (which I believe is now getClassesDirs). This is the line in the Gradle 3 project causing the problem:

apply plugin: "org.grails.grails-plugin"

, so it's outside of my control. Is there a way around this? Full error:

FAILURE: Build failed with an exception.

* Where:
Build file '~/workspace/abc-plugin/build.gradle' line: 23

* What went wrong:
A problem occurred evaluating project ':abc-plugin'.
> Failed to apply plugin [id 'org.grails.grails-plugin']
   > Could not get unknown property 'classesDir' for main classes of type org.gradle.api.internal.tasks.DefaultSourceSetOutput.