diff --git a/.github/workflows/pipeline.yml b/.github/workflows/pipeline.yml
index 59a7658b4..a66ae7b8d 100644
--- a/.github/workflows/pipeline.yml
+++ b/.github/workflows/pipeline.yml
@@ -15,7 +15,7 @@ jobs:
     strategy:
       matrix:
         # build against supported Java LTS versions:
-        java: [ 8, 11, 17 ]
+        java: [ 8, 11, 17, 21 ]
     name: Java ${{ matrix.java }}
     steps:
       - uses: actions/checkout@v3
diff --git a/README.md b/README.md
index 32b59bb8b..5f1f5b0bd 100644
--- a/README.md
+++ b/README.md
@@ -26,7 +26,8 @@ Project goals include:
 * No external dependencies
 * Fast execution and low memory footprint
 * Maintain backward compatibility
-* Designed and tested to use on Java versions 1.8 - 17
+* Designed and tested to use on Java versions 1.8 - 21
+
 
 The files in this package implement JSON encoders and decoders. The package can also convert between JSON and XML, HTTP headers, Cookies, and CDL.