Free 10.6.9 app upgraded to JDK21 still uses Gradle 7.6.3 on MX cloud

I upgraded Mendix IDE to 10.6.9. I took an existing free application which was using JDK11. I upgraded JDK to OpenJDK21 and Gradle to 8.7 locally. The application builds and runs locally without an issue. When I deploy the application to Mendix cloud, I am getting the error 'Could not open proj generic class cache for build file' and Gradle apparently referencing version 7.6.3. My build fails. How do I recover from such situation? I also cleared deployment folder locally. Same result. MX 10.6.9. OpenJDK21.0.3_9. Gradle 8.7.