diff --git a/.github/workflows/PR.yml b/.github/workflows/PR.yml
index 7ef31f82..49b561c2 100644
--- a/.github/workflows/PR.yml
+++ b/.github/workflows/PR.yml
@@ -10,11 +10,11 @@ jobs:
     steps:
     - uses: actions/checkout@v4
 
-    - name: Set up JDK 17
+    - name: Set up JDK 23
       uses: actions/setup-java@v4
       with:
         distribution: 'zulu'
-        java-version: 17
+        java-version: 23
 
     - name: Setup gradle
       uses: gradle/actions/setup-gradle@v4
diff --git a/.github/workflows/SNAPSHOT.yml b/.github/workflows/SNAPSHOT.yml
index 02042492..4b8e7fd3 100644
--- a/.github/workflows/SNAPSHOT.yml
+++ b/.github/workflows/SNAPSHOT.yml
@@ -12,11 +12,11 @@ jobs:
 
     steps:
     - uses: actions/checkout@v4
-    - name: Set up JDK 17
+    - name: Set up JDK 23
       uses: actions/setup-java@v4
       with:
         distribution: 'zulu'
-        java-version: 17
+        java-version: 23
 
     - name: Setup gradle
       uses: gradle/actions/setup-gradle@v4
diff --git a/build.gradle b/build.gradle
index 2fd02ca9..15dcb437 100644
--- a/build.gradle
+++ b/build.gradle
@@ -1,3 +1,5 @@
+import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
+
 plugins {
   alias(libs.plugins.kotlinJvm) apply false
   alias(libs.plugins.spotless)
@@ -35,7 +37,16 @@ allprojects {
 subprojects {
   apply(plugin: "org.jetbrains.kotlin.jvm")
 
-  kotlin.jvmToolchain(17)
+  tasks.withType(JavaCompile).configureEach {
+    sourceCompatibility = '11'
+    targetCompatibility = '11'
+  }
+
+  tasks.withType(KotlinCompile).configureEach {
+    kotlinOptions {
+      jvmTarget = '11'
+    }
+  }
 
   tasks.withType(Test).configureEach {
     testLogging {
diff --git a/core/build.gradle b/core/build.gradle
index f5991f65..b8a6ffca 100644
--- a/core/build.gradle
+++ b/core/build.gradle
@@ -1,3 +1,5 @@
+import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
+
 plugins {
   alias(libs.plugins.kotlinJvm)
   alias(libs.plugins.grammarKitComposer)
diff --git a/sample-headless/src/test/kotlin/com/alecstrong/sql/psi/sample/headless/SampleHeadlessParserTest.kt b/sample-headless/src/test/kotlin/com/alecstrong/sql/psi/sample/headless/SampleHeadlessParserTest.kt
index 6fd79a70..4dc48bb4 100644
--- a/sample-headless/src/test/kotlin/com/alecstrong/sql/psi/sample/headless/SampleHeadlessParserTest.kt
+++ b/sample-headless/src/test/kotlin/com/alecstrong/sql/psi/sample/headless/SampleHeadlessParserTest.kt
@@ -2,8 +2,10 @@ package com.alecstrong.sql.psi.sample.headless
 
 import com.alecstrong.sql.psi.core.psi.SqlLiteralExpr
 import com.alecstrong.sql.psi.sample.core.psi.CustomExpr
-import com.intellij.psi.util.childrenOfType
+import com.intellij.psi.PsiElement
+import com.intellij.psi.util.PsiTreeUtil
 import java.io.File
+import kotlin.reflect.KClass
 import kotlin.test.Test
 import kotlin.test.assertEquals
 import kotlin.test.fail
@@ -21,7 +23,7 @@ class SampleHeadlessParserTest {
           stmt.createTableStmt != null -> {
             val createTableStmt = stmt.createTableStmt!!
             for (columnDef in createTableStmt.columnDefList) {
-              val literalExpr = columnDef.childrenOfType<SqlLiteralExpr>().single()
+              val literalExpr = columnDef.childrenOfType(SqlLiteralExpr::class).single()
               assertEquals(42, literalExpr.literalValue.numericLiteral!!.text.toInt())
             }
           }
@@ -32,7 +34,7 @@ class SampleHeadlessParserTest {
             for (expr in exprs) {
               if (expr is CustomExpr) {
                 val fooRule = expr.fooRule
-                val literalExpr = fooRule.childrenOfType<SqlLiteralExpr>().single().childrenOfType<SqlLiteralExpr>().single()
+                val literalExpr = fooRule.childrenOfType(SqlLiteralExpr::class).single().childrenOfType(SqlLiteralExpr::class).single()
                 assertEquals(13, literalExpr.literalValue.numericLiteral!!.text.toInt())
               }
             }
@@ -42,3 +44,5 @@ class SampleHeadlessParserTest {
     }
   }
 }
+
+fun <T : PsiElement> PsiElement.childrenOfType(kClass: KClass<T>): List<T> = PsiTreeUtil.getChildrenOfTypeAsList(this, kClass.java)