diff --git a/RoaringBitmap/build.gradle.kts b/RoaringBitmap/build.gradle.kts
index ca4f7cefe..77f6a383e 100644
--- a/RoaringBitmap/build.gradle.kts
+++ b/RoaringBitmap/build.gradle.kts
@@ -32,7 +32,7 @@ tasks.named<Jar>("sourcesJar") {
 // Unset Java 8 release applied from root project to allow modularity plugin to
 // control the class file versions.
 tasks.named<JavaCompile>("compileJava") {
-    options.release.set(null as Int?)
+    options.release.set(21)
 }
 
 configure<org.javamodularity.moduleplugin.extensions.ModularityExtension> {
@@ -42,7 +42,7 @@ configure<org.javamodularity.moduleplugin.extensions.ModularityExtension> {
 // Unset Java 8 release applied from root project to allow modularity plugin to
 // control the class file versions.
 tasks.named<JavaCompile>("compileModuleInfoJava") {
-    options.release.set(null as Int?)
+    options.release.set(21)
 }
 
 tasks.test {