diff --git a/.github/workflows/gradle.yml b/.github/workflows/gradle.yml
index bae08f26..0d1574d0 100644
--- a/.github/workflows/gradle.yml
+++ b/.github/workflows/gradle.yml
@@ -11,21 +11,21 @@ jobs:
   build:
     strategy:
       matrix:
-        java: [8, 11, 17]
+        java: [8, 11, 17, 21]
         os: [ubuntu-latest, windows-latest, macos-latest]
     runs-on: ${{ matrix.os }}
     env:
-      gradle_version: 7.6 # set to empty to build with most recent version of gradle
+      gradle_version: 8.7 # set to empty to build with most recent version of gradle
       gradle_commands: publishToMavenLocal exec # default is build
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Set up JDK ${{ matrix.java }}
-        uses: actions/setup-java@v3
+        uses: actions/setup-java@v4
         with:
           java-version: ${{ matrix.java }}
           distribution: 'zulu'
           cache: 'gradle'
-      - uses: gradle/gradle-build-action@v2
+      - uses: gradle/gradle-build-action@v3
         with:
           gradle-version: ${{ env.gradle_version }}
       - name: Run commands
diff --git a/.github/workflows/maven.yml b/.github/workflows/maven.yml
index 9fbc88af..7c092605 100644
--- a/.github/workflows/maven.yml
+++ b/.github/workflows/maven.yml
@@ -13,15 +13,15 @@ jobs:
   build:
     strategy:
       matrix:
-        java: [8, 11, 17]
+        java: [8, 11, 17, 21]
         os: [ubuntu-latest, windows-latest, macos-latest]
     runs-on: ${{ matrix.os }}
     env:
       maven_commands: install # default is install
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Set up JDK ${{ matrix.java }}
-        uses: actions/setup-java@v3
+        uses: actions/setup-java@v4
         with:
           java-version: ${{ matrix.java }}
           distribution: 'zulu'
@@ -35,9 +35,9 @@ jobs:
     env:
       server: ome.releases
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Set up Repository
-        uses: actions/setup-java@v3
+        uses: actions/setup-java@v4
         with:
           java-version: 8
           distribution: 'zulu'
@@ -49,4 +49,3 @@ jobs:
         env:
           MAVEN_USERNAME: ${{ secrets.CI_DEPLOY_USER }}
           MAVEN_PASSWORD: ${{ secrets.CI_DEPLOY_PASS }}
-
diff --git a/build.gradle b/build.gradle
index 0ef34406..c0c8f5a6 100644
--- a/build.gradle
+++ b/build.gradle
@@ -21,12 +21,12 @@ dependencies {
 }
 
 task sourcesJar(type: Jar, dependsOn: classes) {
-    classifier = 'sources'
+    archiveClassifier = 'sources'
     from sourceSets.main.allSource
 }
 
 task javadocJar(type: Jar, dependsOn: javadoc) {
-    classifier = 'javadoc'
+    archiveClassifier = 'javadoc'
     from javadoc.destinationDir
 }