diff --git a/.circleci/config.pkl b/.circleci/config.pkl
index 006ea2b47..ebe9ae1c5 100644
--- a/.circleci/config.pkl
+++ b/.circleci/config.pkl
@@ -105,18 +105,13 @@ local buildNativeJobs: Mapping<String, BuildNativeJob> = new {
 }
 
 local gradleCheckJobs: Mapping<String, GradleCheckJob> = new {
-  ["gradle-check-jdk17"] {
-    javaVersion = "17.0"
-    isRelease = false
-    os = "linux"
-  }
-  ["gradle-check-jdk21"] {
+  ["gradle-check"] {
     javaVersion = "21.0"
     isRelease = false
     os = "linux"
   }
-  ["gradle-check-jdk17-windows"] {
-    javaVersion = "17.0"
+  ["gradle-check-windows"] {
+    javaVersion = "21.0"
     isRelease = false
     os = "windows"
   }
diff --git a/.circleci/config.yml b/.circleci/config.yml
index d0508b76f..87174960f 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -12,7 +12,7 @@ jobs:
     - run:
         command: |-
           export PATH=~/staticdeps/bin:$PATH
-          ./gradlew --info --stacktrace -DtestReportsDir=${HOME}/test-results -DreleaseBuild=true pkl-cli:macExecutableAmd64 pkl-core:testMacExecutableAmd64 pkl-server:testMacExecutableAmd64
+          ./gradlew --info --stacktrace -DtestReportsDir=${HOME}/test-results -DpklMultiJdkTesting=true -DreleaseBuild=true pkl-cli:macExecutableAmd64 pkl-core:testMacExecutableAmd64 pkl-server:testMacExecutableAmd64
         name: gradle buildNative
     - persist_to_workspace:
         root: '.'
@@ -88,7 +88,7 @@ jobs:
     - run:
         command: |-
           export PATH=~/staticdeps/bin:$PATH
-          ./gradlew --info --stacktrace -DtestReportsDir=${HOME}/test-results -DreleaseBuild=true pkl-cli:linuxExecutableAmd64 pkl-core:testLinuxExecutableAmd64 pkl-server:testLinuxExecutableAmd64
+          ./gradlew --info --stacktrace -DtestReportsDir=${HOME}/test-results -DpklMultiJdkTesting=true -DreleaseBuild=true pkl-cli:linuxExecutableAmd64 pkl-core:testLinuxExecutableAmd64 pkl-server:testLinuxExecutableAmd64
         name: gradle buildNative
     - persist_to_workspace:
         root: '.'
@@ -108,7 +108,7 @@ jobs:
     - run:
         command: |-
           export PATH=~/staticdeps/bin:$PATH
-          ./gradlew --info --stacktrace -DtestReportsDir=${HOME}/test-results -DreleaseBuild=true pkl-cli:macExecutableAarch64 pkl-core:testMacExecutableAarch64 pkl-server:testMacExecutableAarch64
+          ./gradlew --info --stacktrace -DtestReportsDir=${HOME}/test-results -DpklMultiJdkTesting=true -DreleaseBuild=true pkl-cli:macExecutableAarch64 pkl-core:testMacExecutableAarch64 pkl-server:testMacExecutableAarch64
         name: gradle buildNative
     - persist_to_workspace:
         root: '.'
@@ -168,7 +168,7 @@ jobs:
     - run:
         command: |-
           export PATH=~/staticdeps/bin:$PATH
-          ./gradlew --info --stacktrace -DtestReportsDir=${HOME}/test-results -DreleaseBuild=true pkl-cli:linuxExecutableAarch64 pkl-core:testLinuxExecutableAarch64 pkl-server:testLinuxExecutableAarch64
+          ./gradlew --info --stacktrace -DtestReportsDir=${HOME}/test-results -DpklMultiJdkTesting=true -DreleaseBuild=true pkl-cli:linuxExecutableAarch64 pkl-core:testLinuxExecutableAarch64 pkl-server:testLinuxExecutableAarch64
         name: gradle buildNative
     - persist_to_workspace:
         root: '.'
@@ -245,7 +245,7 @@ jobs:
     - run:
         command: |-
           export PATH=~/staticdeps/bin:$PATH
-          ./gradlew --info --stacktrace -DtestReportsDir=${HOME}/test-results -DreleaseBuild=true pkl-cli:alpineExecutableAmd64 pkl-core:testAlpineExecutableAmd64 pkl-server:testAlpineExecutableAmd64
+          ./gradlew --info --stacktrace -DtestReportsDir=${HOME}/test-results -DpklMultiJdkTesting=true -DreleaseBuild=true pkl-cli:alpineExecutableAmd64 pkl-core:testAlpineExecutableAmd64 pkl-server:testAlpineExecutableAmd64
         name: gradle buildNative
     - persist_to_workspace:
         root: '.'
@@ -277,7 +277,7 @@ jobs:
     - run:
         command: |-
           export PATH=~/staticdeps/bin:$PATH
-          ./gradlew --info --stacktrace -DtestReportsDir=${HOME}/test-results -DreleaseBuild=true pkl-cli:windowsExecutableAmd64 pkl-core:testWindowsExecutableAmd64 pkl-server:testWindowsExecutableAmd64
+          ./gradlew --info --stacktrace -DtestReportsDir=${HOME}/test-results -DpklMultiJdkTesting=true -DreleaseBuild=true pkl-cli:windowsExecutableAmd64 pkl-core:testWindowsExecutableAmd64 pkl-server:testWindowsExecutableAmd64
         name: gradle buildNative
         shell: bash.exe
     - persist_to_workspace:
@@ -301,7 +301,7 @@ jobs:
     - run:
         command: |-
           export PATH=~/staticdeps/bin:$PATH
-          ./gradlew --info --stacktrace -DtestReportsDir=${HOME}/test-results pkl-cli:macExecutableAmd64 pkl-core:testMacExecutableAmd64 pkl-server:testMacExecutableAmd64
+          ./gradlew --info --stacktrace -DtestReportsDir=${HOME}/test-results -DpklMultiJdkTesting=true pkl-cli:macExecutableAmd64 pkl-core:testMacExecutableAmd64 pkl-server:testMacExecutableAmd64
         name: gradle buildNative
     - persist_to_workspace:
         root: '.'
@@ -377,7 +377,7 @@ jobs:
     - run:
         command: |-
           export PATH=~/staticdeps/bin:$PATH
-          ./gradlew --info --stacktrace -DtestReportsDir=${HOME}/test-results pkl-cli:linuxExecutableAmd64 pkl-core:testLinuxExecutableAmd64 pkl-server:testLinuxExecutableAmd64
+          ./gradlew --info --stacktrace -DtestReportsDir=${HOME}/test-results -DpklMultiJdkTesting=true pkl-cli:linuxExecutableAmd64 pkl-core:testLinuxExecutableAmd64 pkl-server:testLinuxExecutableAmd64
         name: gradle buildNative
     - persist_to_workspace:
         root: '.'
@@ -397,7 +397,7 @@ jobs:
     - run:
         command: |-
           export PATH=~/staticdeps/bin:$PATH
-          ./gradlew --info --stacktrace -DtestReportsDir=${HOME}/test-results pkl-cli:macExecutableAarch64 pkl-core:testMacExecutableAarch64 pkl-server:testMacExecutableAarch64
+          ./gradlew --info --stacktrace -DtestReportsDir=${HOME}/test-results -DpklMultiJdkTesting=true pkl-cli:macExecutableAarch64 pkl-core:testMacExecutableAarch64 pkl-server:testMacExecutableAarch64
         name: gradle buildNative
     - persist_to_workspace:
         root: '.'
@@ -457,7 +457,7 @@ jobs:
     - run:
         command: |-
           export PATH=~/staticdeps/bin:$PATH
-          ./gradlew --info --stacktrace -DtestReportsDir=${HOME}/test-results pkl-cli:linuxExecutableAarch64 pkl-core:testLinuxExecutableAarch64 pkl-server:testLinuxExecutableAarch64
+          ./gradlew --info --stacktrace -DtestReportsDir=${HOME}/test-results -DpklMultiJdkTesting=true pkl-cli:linuxExecutableAarch64 pkl-core:testLinuxExecutableAarch64 pkl-server:testLinuxExecutableAarch64
         name: gradle buildNative
     - persist_to_workspace:
         root: '.'
@@ -534,7 +534,7 @@ jobs:
     - run:
         command: |-
           export PATH=~/staticdeps/bin:$PATH
-          ./gradlew --info --stacktrace -DtestReportsDir=${HOME}/test-results pkl-cli:alpineExecutableAmd64 pkl-core:testAlpineExecutableAmd64 pkl-server:testAlpineExecutableAmd64
+          ./gradlew --info --stacktrace -DtestReportsDir=${HOME}/test-results -DpklMultiJdkTesting=true pkl-cli:alpineExecutableAmd64 pkl-core:testAlpineExecutableAmd64 pkl-server:testAlpineExecutableAmd64
         name: gradle buildNative
     - persist_to_workspace:
         root: '.'
@@ -566,7 +566,7 @@ jobs:
     - run:
         command: |-
           export PATH=~/staticdeps/bin:$PATH
-          ./gradlew --info --stacktrace -DtestReportsDir=${HOME}/test-results pkl-cli:windowsExecutableAmd64 pkl-core:testWindowsExecutableAmd64 pkl-server:testWindowsExecutableAmd64
+          ./gradlew --info --stacktrace -DtestReportsDir=${HOME}/test-results -DpklMultiJdkTesting=true pkl-cli:windowsExecutableAmd64 pkl-core:testWindowsExecutableAmd64 pkl-server:testWindowsExecutableAmd64
         name: gradle buildNative
         shell: bash.exe
     - persist_to_workspace:
@@ -581,23 +581,11 @@ jobs:
     resource_class: windows.large
     machine:
       image: windows-server-2022-gui:current
-  gradle-check-jdk17:
+  gradle-check:
     steps:
     - checkout
     - run:
-        command: ./gradlew --info --stacktrace -DtestReportsDir=${HOME}/test-results check
-        name: gradle check
-    - store_test_results:
-        path: ~/test-results
-    environment:
-      LANG: en_US.UTF-8
-    docker:
-    - image: cimg/openjdk:17.0
-  gradle-check-jdk21:
-    steps:
-    - checkout
-    - run:
-        command: ./gradlew --info --stacktrace -DtestReportsDir=${HOME}/test-results check
+        command: ./gradlew --info --stacktrace -DtestReportsDir=${HOME}/test-results -DpklMultiJdkTesting=true check
         name: gradle check
     - store_test_results:
         path: ~/test-results
@@ -605,14 +593,14 @@ jobs:
       LANG: en_US.UTF-8
     docker:
     - image: cimg/openjdk:21.0
-  gradle-check-jdk17-windows:
+  gradle-check-windows:
     steps:
     - checkout
     - run:
         command: |-
           # install jdk
           curl -Lf \
-          https://github.com/adoptium/temurin17-binaries/releases/download/jdk-17.0.9%2B9.1/OpenJDK17U-jdk_x64_windows_hotspot_17.0.9_9.zip -o /tmp/jdk.zip
+          https://github.com/adoptium/temurin21-binaries/releases/download/jdk-21.0.5%2B11/OpenJDK21U-jdk_x64_windows_hotspot_21.0.5_11.zip -o /tmp/jdk.zip
 
           unzip /tmp/jdk.zip -d /tmp/jdk \
             && cd /tmp/jdk/jdk-* \
@@ -621,7 +609,7 @@ jobs:
         name: Set up environment
         shell: bash.exe
     - run:
-        command: ./gradlew --info --stacktrace -DtestReportsDir=${HOME}/test-results check
+        command: ./gradlew --info --stacktrace -DtestReportsDir=${HOME}/test-results -DpklMultiJdkTesting=true check
         name: gradle check
     - store_test_results:
         path: ~/test-results
@@ -635,7 +623,7 @@ jobs:
     steps:
     - checkout
     - run:
-        command: ./gradlew --info --stacktrace -DtestReportsDir=${HOME}/test-results bench:jmh
+        command: ./gradlew --info --stacktrace -DtestReportsDir=${HOME}/test-results -DpklMultiJdkTesting=true bench:jmh
         name: bench:jmh
     - store_test_results:
         path: ~/test-results
@@ -648,7 +636,7 @@ jobs:
     - checkout
     - run:
         command: |-
-          ./gradlew --info --stacktrace -DtestReportsDir=${HOME}/test-results :pkl-gradle:build \
+          ./gradlew --info --stacktrace -DtestReportsDir=${HOME}/test-results -DpklMultiJdkTesting=true :pkl-gradle:build \
             :pkl-gradle:compatibilityTestReleases
         name: gradle compatibility
     - store_test_results:
@@ -663,7 +651,7 @@ jobs:
     - attach_workspace:
         at: '.'
     - run:
-        command: ./gradlew --info --stacktrace -DtestReportsDir=${HOME}/test-results publishToSonatype
+        command: ./gradlew --info --stacktrace -DtestReportsDir=${HOME}/test-results -DpklMultiJdkTesting=true publishToSonatype
     - persist_to_workspace:
         root: '.'
         paths:
@@ -680,7 +668,7 @@ jobs:
     - attach_workspace:
         at: '.'
     - run:
-        command: ./gradlew --info --stacktrace -DtestReportsDir=${HOME}/test-results -DreleaseBuild=true publishToSonatype closeAndReleaseSonatypeStagingRepository
+        command: ./gradlew --info --stacktrace -DtestReportsDir=${HOME}/test-results -DpklMultiJdkTesting=true -DreleaseBuild=true publishToSonatype closeAndReleaseSonatypeStagingRepository
     - persist_to_workspace:
         root: '.'
         paths:
@@ -742,13 +730,10 @@ workflows:
         type: approval
     - pr-approval/authenticate:
         context: pkl-pr-approval
-    - gradle-check-jdk17:
+    - gradle-check:
         requires:
         - hold
-    - gradle-check-jdk21:
-        requires:
-        - hold
-    - gradle-check-jdk17-windows:
+    - gradle-check-windows:
         requires:
         - hold
     when:
@@ -757,9 +742,8 @@ workflows:
         pattern: ^pull/\d+(/head)?$
   main:
     jobs:
-    - gradle-check-jdk17
-    - gradle-check-jdk21
-    - gradle-check-jdk17-windows
+    - gradle-check
+    - gradle-check-windows
     - bench
     - gradle-compatibility
     - pkl-cli-macOS-amd64-snapshot
@@ -770,9 +754,8 @@ workflows:
     - pkl-cli-windows-amd64-snapshot
     - deploy-snapshot:
         requires:
-        - gradle-check-jdk17
-        - gradle-check-jdk21
-        - gradle-check-jdk17-windows
+        - gradle-check
+        - gradle-check-windows
         - bench
         - gradle-compatibility
         - pkl-cli-macOS-amd64-snapshot
@@ -793,19 +776,13 @@ workflows:
       - << pipeline.git.branch >>
   release:
     jobs:
-    - gradle-check-jdk17:
-        filters:
-          branches:
-            ignore: /.*/
-          tags:
-            only: /^v?\d+\.\d+\.\d+$/
-    - gradle-check-jdk21:
+    - gradle-check:
         filters:
           branches:
             ignore: /.*/
           tags:
             only: /^v?\d+\.\d+\.\d+$/
-    - gradle-check-jdk17-windows:
+    - gradle-check-windows:
         filters:
           branches:
             ignore: /.*/
@@ -861,9 +838,8 @@ workflows:
             only: /^v?\d+\.\d+\.\d+$/
     - github-release:
         requires:
-        - gradle-check-jdk17
-        - gradle-check-jdk21
-        - gradle-check-jdk17-windows
+        - gradle-check
+        - gradle-check-windows
         - bench
         - gradle-compatibility
         - pkl-cli-macOS-amd64-release
@@ -899,9 +875,8 @@ workflows:
             only: /^v?\d+\.\d+\.\d+$/
   release-branch:
     jobs:
-    - gradle-check-jdk17
-    - gradle-check-jdk21
-    - gradle-check-jdk17-windows
+    - gradle-check
+    - gradle-check-windows
     - bench
     - gradle-compatibility
     - pkl-cli-macOS-amd64-release
diff --git a/.circleci/jobs/GradleJob.pkl b/.circleci/jobs/GradleJob.pkl
index 92621cebf..1620cd8bd 100644
--- a/.circleci/jobs/GradleJob.pkl
+++ b/.circleci/jobs/GradleJob.pkl
@@ -47,6 +47,7 @@ fixed gradleArgs = new Listing {
   "--info"
   "--stacktrace"
   "-DtestReportsDir=${HOME}/test-results"
+  "-DpklMultiJdkTesting=true"
   when (isRelease) {
     "-DreleaseBuild=true"
   }