diff --git a/build.gradle b/build.gradle
index d5dea214..d0307866 100644
--- a/build.gradle
+++ b/build.gradle
@@ -21,11 +21,12 @@ buildscript {
             opensearch_build += "-SNAPSHOT"
         }
 
-        opensearch_java_version = '2.19.0'
         apache_http_components_version = '5.4.1'
         apache_http_core_version = '5.3.2'
+        opensearch_java_version = '2.21.0'
         aws_sdk_version = '2.30.18'
-        junit_version = '5.11.4' // version catalog is 4.x
+        junit_version = '5.12.0' // version catalog is 4.x
+        junit_platform_version = '1.12.0' // version catalog brings in earlier
     }
 
     repositories {
@@ -98,9 +99,13 @@ subprojects {
         implementation "org.apache.httpcomponents.client5:httpclient5:${apache_http_components_version}"
         implementation "org.apache.httpcomponents.core5:httpcore5:${apache_http_core_version}"
 
-        testImplementation "org.opensearch.test:framework:${opensearch_version}"
-        testImplementation "org.junit.jupiter:junit-jupiter:${junit_version}"
-        testImplementation "org.mockito:mockito-core:${versions.mockito}"
+        // prevent conflicts with upstream JUnit 4
+        testImplementation("org.opensearch.test:framework:${opensearch_version}") {
+            exclude group: "org.junit.platform"
+        }
+        testImplementation("org.junit.jupiter:junit-jupiter:${junit_version}")
+        testImplementation("org.junit.platform:junit-platform-launcher:${junit_platform_version}")
+        testImplementation("org.mockito:mockito-core:${versions.mockito}")
     }
 
     configurations {