diff --git a/.github/renovate.json5 b/.github/renovate.json5
index 2cda140c7..04a5ee40e 100644
--- a/.github/renovate.json5
+++ b/.github/renovate.json5
@@ -84,6 +84,13 @@
       "matchPackagePrefixes": ["org.openjdk.jmc"],
       "matchUpdateTypes": ["major"],
       "enabled": false
+    },
+    {
+      // pinned version for compatibility
+      "matchFileNames": ["jmx-scraper/test-webapp/build.gradle.kts"],
+      "matchPackagePrefixes": ["jakarta.servlet:"],
+      "matchCurrentVersion": "5.0.0",
+      "enabled": false
     }
   ]
 }
diff --git a/jmx-scraper/test-app/build.gradle.kts b/jmx-scraper/test-app/build.gradle.kts
index 721f6fed7..3f0f35a06 100644
--- a/jmx-scraper/test-app/build.gradle.kts
+++ b/jmx-scraper/test-app/build.gradle.kts
@@ -5,9 +5,8 @@ plugins {
 description = "JMX metrics scraper - test application"
 
 java {
-  toolchain {
-    languageVersion = JavaLanguageVersion.of(8)
-  }
+  sourceCompatibility = JavaVersion.VERSION_1_8
+  targetCompatibility = JavaVersion.VERSION_1_8
 }
 
 tasks {
diff --git a/jmx-scraper/test-webapp/build.gradle.kts b/jmx-scraper/test-webapp/build.gradle.kts
index ac863095b..b0223e169 100644
--- a/jmx-scraper/test-webapp/build.gradle.kts
+++ b/jmx-scraper/test-webapp/build.gradle.kts
@@ -9,7 +9,7 @@ dependencies {
 }
 
 java {
-  toolchain {
-    languageVersion = JavaLanguageVersion.of(8)
-  }
+  // keeping java 8 compatibility to allow running this sample app in most containers
+  sourceCompatibility = JavaVersion.VERSION_1_8
+  targetCompatibility = JavaVersion.VERSION_1_8
 }