diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 086282e8d4e..21a4e4d4dab 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -44,7 +44,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [8,11]
+        java: [8,11,17,21]
     steps:
       - name: Checkout
         uses: actions/checkout@v4
diff --git a/kubernetes-client/src/test/java/io/fabric8/kubernetes/client/behavior/UploadTest.java b/kubernetes-client/src/test/java/io/fabric8/kubernetes/client/behavior/UploadTest.java
index 85bf256ae31..9d87880dd13 100644
--- a/kubernetes-client/src/test/java/io/fabric8/kubernetes/client/behavior/UploadTest.java
+++ b/kubernetes-client/src/test/java/io/fabric8/kubernetes/client/behavior/UploadTest.java
@@ -37,6 +37,7 @@
 import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Nested;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.condition.DisabledOnJre;
 import org.junit.jupiter.api.io.TempDir;
 import org.mockito.ArgumentCaptor;
 
@@ -61,6 +62,7 @@
 import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
 import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.junit.jupiter.api.condition.JRE.JAVA_21;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.verify;
@@ -296,6 +298,7 @@ void longFileNamesSupported() throws Exception {
               .hasFieldOrPropertyWithValue("name", longFileName);
         }
 
+        @DisabledOnJre(JAVA_21)
         @Test
         @DisplayName("Big numbers supported (POSIX)")
         void bigNumbersSupported(@TempDir Path tempDir) throws Exception {
diff --git a/platforms/karaf/pom.xml b/platforms/karaf/pom.xml
index 30fa031e65e..50f9342241f 100644
--- a/platforms/karaf/pom.xml
+++ b/platforms/karaf/pom.xml
@@ -36,7 +36,8 @@
   <properties>
     <karaf.version>4.4.5</karaf.version>
     <osgi.version>6.0.0</osgi.version>
-    <pax.exam.version>4.13.5</pax.exam.version>
+    <!--  NOT Updated because of: https://github.com/ops4j/org.ops4j.pax.exam2/issues/1020#issuecomment-1011133020 causing instability in CI -->
+    <pax.exam.version>4.13.3</pax.exam.version>
   </properties>
 
 </project>
diff --git a/pom.xml b/pom.xml
index db2080ad555..835c8b751bd 100644
--- a/pom.xml
+++ b/pom.xml
@@ -113,7 +113,8 @@
     <awaitility.version>4.2.1</awaitility.version>
     <approvaltests.version>23.0.1</approvaltests.version>
     <mockito.version>4.11.0</mockito.version>
-    <spock.version>2.3-groovy-4.0</spock.version>
+    <mockito-inline.version>4.11.0</mockito-inline.version>
+    <spock.version>2.4-M4-groovy-4.0</spock.version>
 
     <conscrypt-openjdk-uber.bundle.version>1.4.2_1</conscrypt-openjdk-uber.bundle.version>
     <generex.version>1.0.2</generex.version>
@@ -164,8 +165,7 @@
     <maven.plugin.plugin.version>3.12.0</maven.plugin.plugin.version>
     <gmavenplus-plugin.version>3.0.2</gmavenplus-plugin.version>
     <gradle-api-maven-plugin.version>0.0.5</gradle-api-maven-plugin.version>
-    <jandex.plugin.version>1.2.3</jandex.plugin.version>
-    <jandex.version>2.4.4.Final</jandex.version>
+    <jandex.plugin.version>3.1.7</jandex.plugin.version>
     <jacoco-maven-plugin.version>0.8.12</jacoco-maven-plugin.version>
     <jkube.version>1.16.2</jkube.version>
     <sonar-maven-plugin.version>3.11.0.3922</sonar-maven-plugin.version>
@@ -903,7 +903,7 @@
       <dependency>
         <groupId>org.mockito</groupId>
         <artifactId>mockito-inline</artifactId>
-        <version>${mockito.version}</version>
+        <version>${mockito-inline.version}</version>
         <scope>test</scope>
       </dependency>
 
@@ -1095,7 +1095,7 @@
           <version>${maven.invoker.plugin.version}</version>
         </plugin>
         <plugin>
-          <groupId>org.jboss.jandex</groupId>
+          <groupId>io.smallrye</groupId>
           <artifactId>jandex-maven-plugin</artifactId>
           <version>${jandex.plugin.version}</version>
           <executions>
@@ -1107,13 +1107,6 @@
               <inherited>true</inherited>
             </execution>
           </executions>
-          <dependencies>
-            <dependency>
-              <groupId>org.jboss</groupId>
-              <artifactId>jandex</artifactId>
-              <version>${jandex.version}</version>
-            </dependency>
-          </dependencies>
         </plugin>
         <plugin>
           <groupId>org.jacoco</groupId>
@@ -1172,7 +1165,7 @@
       </plugin>
       <!-- Create jandex index for faster performance in environments that use it -->
       <plugin>
-        <groupId>org.jboss.jandex</groupId>
+        <groupId>io.smallrye</groupId>
         <artifactId>jandex-maven-plugin</artifactId>
       </plugin>
       <plugin>
@@ -1581,6 +1574,17 @@
         </plugins>
       </build>
     </profile>
+    <profile>
+      <id>java-17</id>
+      <activation>
+        <jdk>[17,)</jdk>
+      </activation>
+      <properties>
+        <mockito.version>5.11.0</mockito.version>
+        <mockito-inline.version>5.2.0</mockito-inline.version>
+        <karaf.itest.skip>true</karaf.itest.skip>
+      </properties>
+    </profile>
     <profile>
       <id>javadoc-test</id>
       <build>