diff --git a/.github/workflows/check-build-test.yml b/.github/workflows/check-build-test.yml
index 5eba7d81e..8d601389d 100644
--- a/.github/workflows/check-build-test.yml
+++ b/.github/workflows/check-build-test.yml
@@ -124,7 +124,8 @@ jobs:
       fail-fast: false
       matrix:
         include:
-          - { java-version: 'temurin:1.11', sbt-opts: '-J-XX:+UnlockExperimentalVMOptions -J-XX:+UseJVMCICompiler' }
+          - { scalaVersion: '2.13', java-version: 'temurin:1.11', sbt-opts: '-J-XX:+UnlockExperimentalVMOptions -J-XX:+UseJVMCICompiler' }
+          - { scalaVersion: '2.13', java-version: 'temurin:1.21', sbt-opts: '' }
     steps:
       - name: Checkout
         # https://github.com/actions/checkout/releases
@@ -152,7 +153,7 @@ jobs:
           jvm: ${{ matrix.java-version }}
 
       - name: Run tests with Scala ${{ matrix.scala-version }} and Java ${{ matrix.java-version }}
-        run: sbt ${{ matrix.sbt-opts }} "test"
+        run: sbt ++${{ matrix.scalaVersion }} ${{ matrix.sbt-opts }} "test"
 
       - name: Print logs on failure
         if: ${{ failure() }}
diff --git a/project/project-info.conf b/project/project-info.conf
index e36d35a4e..9ca849f73 100644
--- a/project/project-info.conf
+++ b/project/project-info.conf
@@ -1,7 +1,7 @@
 project-info {
   version: "current"
   shared-info {
-    jdk-versions: ["Eclipse Temurin JDK 11", "Eclipse Temurin JDK 17"]
+    jdk-versions: ["Eclipse Temurin JDK 11", "Eclipse Temurin JDK 17", "Eclipse Temurin JDK 21"]
     snapshots: {
       url: "snapshots.html"
       text: "Snapshots are available"
diff --git a/scripts/link-validator.conf b/scripts/link-validator.conf
index 0ae00d5be..3ca4dd61d 100644
--- a/scripts/link-validator.conf
+++ b/scripts/link-validator.conf
@@ -20,7 +20,7 @@ site-link-validator {
 
   ignore-prefixes = [
     # runtime is NOT part of the published Scaladoc
-    "https://www.scala-lang.org/api/2.13.12/scala/runtime/AbstractFunction2.html"
+    "https://www.scala-lang.org/api/2.13.13/scala/runtime/AbstractFunction2.html"
     # GitHub will block with "429 Too Many Requests"
     "https://github.com/"
     # MVN repository forbids access after a few requests