Struggling to install on Debian "Axelor" using source on Github

I’m trying to build « Axelor » I’ve followed all the steps for installing from source [Install on Linux :: Axelor][1] and have managed to succeed up until this point ./gradlew -x test build

But the build has failed and I’m not sure how or where to investigate to fix this, any help will be much appreciated.

Starting a Gradle Daemon (subsequent builds will be faster)
> Task :buildSrc:compileJava
> Task :buildSrc:compileGroovy NO-SOURCE
> Task :buildSrc:processResources NO-SOURCE
> Task :buildSrc:classes
> Task :buildSrc:jar
> Task :buildSrc:assemble
> Task :buildSrc:compileTestJava NO-SOURCE
> Task :buildSrc:compileTestGroovy NO-SOURCE
> Task :buildSrc:processTestResources NO-SOURCE
> Task :buildSrc:testClasses UP-TO-DATE
> Task :buildSrc:test NO-SOURCE
> Task :buildSrc:check UP-TO-DATE
> Task :buildSrc:build

FAILURE: Build failed with an exception.

* What went wrong:
Could not determine the dependencies of task ':war'.
> Could not resolve all task dependencies for configuration ':runtimeClasspath'.
   > Could not resolve project :modules:axelor-supplier-portal.
     Required by:
         project :
      > Unable to find a matching variant of project :modules:axelor-supplier-portal:
          - Variant 'apiElements' capability com.axelor.apps:axelor-supplier-portal:6.3.1:
              - Incompatible attributes:
                  - Required org.gradle.jvm.version '8' and found incompatible value '11'.
                  - Required org.gradle.usage 'java-runtime' and found incompatible value 'java-api'.
              - Other attributes:
                  - Found org.gradle.category 'library' but wasn't required.
                  - Required org.gradle.dependency.bundling 'external' and found compatible value 

Make sure you have the installation prerequisites for AOS version 6.3.1
JDK 11 is not compatible for this version of AOS 6.3.1