diff --git a/.circleci/config.pkl b/.circleci/config.pkl
index 2d3b232..2157281 100644
--- a/.circleci/config.pkl
+++ b/.circleci/config.pkl
@@ -1,5 +1,5 @@
 //===----------------------------------------------------------------------===//
-// Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
+// Copyright © 2024-2025 Apple Inc. and the Pkl project authors. All rights reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -13,12 +13,12 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 //===----------------------------------------------------------------------===//
-amends "package://pkg.pkl-lang.org/pkl-project-commons/pkl.impl.circleci@1.0.0#/PklCI.pkl"
+amends "package://pkg.pkl-lang.org/pkl-project-commons/pkl.impl.circleci@1.1.1#/PklCI.pkl"
 
 jobs {
   ["build"] {
     docker {
-      new { image = "cimg/openjdk:17.0" }
+      new { image = "cimg/openjdk:21.0" }
     }
     steps {
       "checkout"
diff --git a/.circleci/config.yml b/.circleci/config.yml
index 6088136..7084e77 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -17,7 +17,7 @@ jobs:
         paths:
         - build
     docker:
-    - image: cimg/openjdk:17.0
+    - image: cimg/openjdk:21.0
   release:
     steps:
     - checkout
@@ -66,7 +66,6 @@ workflows:
     - build:
         requires:
         - hold
-        - pr-approval/authenticate
     when:
       matches:
         value: << pipeline.git.branch >>
diff --git a/build.gradle.kts b/build.gradle.kts
index f2fd1b8..f4a732b 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -62,7 +62,7 @@ spotless {
 }
 
 kotlin {
-  jvmToolchain(17)
+  jvmToolchain(21)
 }
 
 repositories {
diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
index 545eee4..4cca218 100644
--- a/gradle/libs.versions.toml
+++ b/gradle/libs.versions.toml
@@ -1,6 +1,6 @@
 [versions]
 pkl = "0.25.1"
-kotlin = "1.9.0"
+kotlin = "2.1.0"
 junit = "5.10.0"
 spotless = "6.25.0"
 
diff --git a/gradle/wrapper/gradle-wrapper.jar b/gradle/wrapper/gradle-wrapper.jar
index d64cd49..a4b76b9 100644
Binary files a/gradle/wrapper/gradle-wrapper.jar and b/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index 1af9e09..cea7a79 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -1,6 +1,6 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.5-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.12-bin.zip
 networkTimeout=10000
 validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
diff --git a/gradlew b/gradlew
index 1aa94a4..f5feea6 100755
--- a/gradlew
+++ b/gradlew
@@ -15,6 +15,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #
+# SPDX-License-Identifier: Apache-2.0
+#
 
 ##############################################################################
 #
@@ -55,7 +57,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/platforms/jvm/plugins-application/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -84,7 +86,8 @@ done
 # shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
 # Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
-APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit
+APP_HOME=$( cd -P "${APP_HOME:-./}" > /dev/null && printf '%s
+' "$PWD" ) || exit
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
 MAX_FD=maximum
diff --git a/gradlew.bat b/gradlew.bat
index 93e3f59..9d21a21 100644
--- a/gradlew.bat
+++ b/gradlew.bat
@@ -13,6 +13,8 @@
 @rem See the License for the specific language governing permissions and
 @rem limitations under the License.
 @rem
+@rem SPDX-License-Identifier: Apache-2.0
+@rem
 
 @if "%DEBUG%"=="" @echo off
 @rem ##########################################################################
@@ -43,11 +45,11 @@ set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
 if %ERRORLEVEL% equ 0 goto execute
 
-echo.
-echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
@@ -57,11 +59,11 @@ set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
 if exist "%JAVA_EXE%" goto execute
 
-echo.
-echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
-echo.
-echo Please set the JAVA_HOME variable in your environment to match the
-echo location of your Java installation.
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
 
 goto fail
 
diff --git a/settings.gradle.kts b/settings.gradle.kts
index 188b31f..ff095b1 100644
--- a/settings.gradle.kts
+++ b/settings.gradle.kts
@@ -5,4 +5,8 @@ pluginManagement {
   }
 }
 
+plugins {
+  id("org.gradle.toolchains.foojay-resolver-convention") version "0.9.0"
+}
+
 rootProject.name = "pkl-project-commons"