diff --git a/bulk-model-sync-gradle/build.gradle.kts b/bulk-model-sync-gradle/build.gradle.kts
index 72a08f4cfc..cdda35091d 100644
--- a/bulk-model-sync-gradle/build.gradle.kts
+++ b/bulk-model-sync-gradle/build.gradle.kts
@@ -3,6 +3,16 @@ plugins {
     `java-gradle-plugin`
 }
 
+tasks.test {
+    // The tests execute the Gradle build for modelix.core which requires Java 21.
+    // It requires Java 21 for the Gradle plugin `dev.petuska.npm.publish`.
+    javaLauncher.set(
+        javaToolchains.launcherFor {
+            languageVersion.set(JavaLanguageVersion.of(21))
+        },
+    )
+}
+
 dependencies {
     implementation(project(":model-client", "jvmRuntimeElements"))
     implementation(project(":bulk-model-sync-lib"))
diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
index af78c80c35..ae10199f6a 100644
--- a/gradle/libs.versions.toml
+++ b/gradle/libs.versions.toml
@@ -15,7 +15,7 @@ modelix-mps-buildtools = { id = "org.modelix.mps.build-tools", version.ref = "mo
 dokka = {id = "org.jetbrains.dokka", version.ref = "dokka"}
 node = {id = "com.github.node-gradle.node", version = "7.1.0"}
 detekt = { id = "io.gitlab.arturbosch.detekt", version.ref = "detekt" }
-npm-publish = { id = "dev.petuska.npm.publish", version = "3.4.3" }
+npm-publish = { id = "dev.petuska.npm.publish", version = "3.5.1" }
 test-logger = { id = "com.adarshr.test-logger", version = "4.0.0" }
 shadow = { id = "com.github.johnrengelman.shadow", version = "8.1.1" }
 intellij = { id = "org.jetbrains.intellij", version = "1.17.4" }