diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index f79ebba..c52b270 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ 11, 17 ]
+        java: [ 17, 21 ]
         build_property: [ "kakadu.version", "ignored.version" ]
 
     steps:
diff --git a/.github/workflows/nightly.yml b/.github/workflows/nightly.yml
index 0ce640e..b791858 100644
--- a/.github/workflows/nightly.yml
+++ b/.github/workflows/nightly.yml
@@ -14,7 +14,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ 11 ]
+        java: [ 17 ]
         build_property: [ "kakadu.version", "ignored.version" ]
     steps:
       - name: Check out source code
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 19323ab..0951063 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        java: [ 11 ]
+        java: [ 17 ]
         build_property: [ "kakadu.version", "ignored.version" ]
     steps:
       - name: Check out source code