diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 713e187..43813b9 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -27,7 +27,7 @@ jobs:
       - uses: actions/setup-java@v3
         with:
           distribution: 'zulu'
-          java-version: '17'
+          java-version: '21'
       - uses: gradle/gradle-build-action@v2
         with:
           gradle-home-cache-cleanup: true
diff --git a/build.gradle.kts b/build.gradle.kts
index bd70da9..4fb0f89 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -1,5 +1,3 @@
-@file:Suppress("UnstableApiUsage", "DSL_SCOPE_VIOLATION")
-
 import com.google.cloud.tools.jib.gradle.BuildImageTask
 import com.netflix.graphql.dgs.codegen.gradle.GenerateJavaTask
 import io.gitlab.arturbosch.detekt.Detekt
@@ -57,22 +55,22 @@ dependencies {
 
 configurations.all {
     resolutionStrategy.eachDependency {
-        if (requested.group == "org.jetbrains.kotlinx" && requested.name.startsWith("kotlinx-coroutines")) {
-            useVersion(libs.versions.kotlinx.coroutines.get())
+        if (this@all.name == "detekt" && requested.group == "org.jetbrains.kotlin") {
+            useVersion("1.9.0")
         }
     }
 }
 
 kotlin {
     jvmToolchain {
-        languageVersion.set(JavaLanguageVersion.of(17))
+        languageVersion.set(JavaLanguageVersion.of(20))
     }
 }
 
 allprojects {
     detekt {
-        source = files("src/")
-        config = files("${project.rootDir}/detekt.yml")
+        source.setFrom(files("src/"))
+        config.setFrom(files("${project.rootDir}/detekt.yml"))
         buildUponDefaultConfig = true
         allRules = true
     }
@@ -84,7 +82,6 @@ allprojects {
     dependencies.add("detektPlugins", libs.detektFormatting)
 }
 
-
 tasks.withType<KotlinCompile>().configureEach {
     compilerOptions {
         languageVersion.set(KotlinVersion.KOTLIN_2_0)
diff --git a/cloudbuild.yaml b/cloudbuild.yaml
index 207ec52..130b9d9 100644
--- a/cloudbuild.yaml
+++ b/cloudbuild.yaml
@@ -1,7 +1,7 @@
 steps:
 
 # build and push the container image
-- name: gradle:jdk17-alpine
+- name: gradle:jdk21-alpine
   entrypoint: gradle
   args: [ 'jib', '--image=${_CONTAINER_IMAGE}:$SHORT_SHA', '--no-configuration-cache' ]
 
diff --git a/gradle.properties b/gradle.properties
index ecbf122..6aa3e6d 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -7,3 +7,4 @@ org.gradle.configuration-cache-problems=warn
 
 # Kotlin code style
 kotlin.code.style=official
+kotlin.experimental.tryK2=true
diff --git a/src/main/kotlin/io/github/reactivecircus/kstreamlined/backend/client/FeedClient.kt b/src/main/kotlin/io/github/reactivecircus/kstreamlined/backend/client/FeedClient.kt
index 7092a6d..4d9fbd6 100644
--- a/src/main/kotlin/io/github/reactivecircus/kstreamlined/backend/client/FeedClient.kt
+++ b/src/main/kotlin/io/github/reactivecircus/kstreamlined/backend/client/FeedClient.kt
@@ -21,6 +21,7 @@ import io.ktor.serialization.kotlinx.xml.xml
 import kotlinx.serialization.decodeFromString
 import nl.adaptivity.xmlutil.ExperimentalXmlUtilApi
 import nl.adaptivity.xmlutil.serialization.DefaultXmlSerializationPolicy
+import nl.adaptivity.xmlutil.serialization.XmlConfig
 import org.apache.commons.text.StringEscapeUtils
 
 interface FeedClient {
@@ -54,7 +55,7 @@ class RealFeedClient(
             val format = DefaultXml.copy {
                 policy = DefaultXmlSerializationPolicy(
                     pedantic = false,
-                    unknownChildHandler = { _, _, _, _, _ -> emptyList() }
+                    unknownChildHandler = XmlConfig.IGNORING_UNKNOWN_CHILD_HANDLER
                 )
             }