diff --git a/examples/kotlin-kts/build.gradle.kts b/examples/kotlin-kts/build.gradle.kts
index 66977c03..c54f516f 100644
--- a/examples/kotlin-kts/build.gradle.kts
+++ b/examples/kotlin-kts/build.gradle.kts
@@ -8,11 +8,11 @@ import org.jetbrains.kotlin.gradle.tasks.*
 plugins {
     java
     kotlin("jvm")
-    kotlin("plugin.allopen") version "1.9.0"
+    kotlin("plugin.allopen") version "1.9.21"
     id("org.jetbrains.kotlinx.benchmark")
 }
 
-sourceSets.all {
+sourceSets.configureEach {
     java.setSrcDirs(listOf("$name/src"))
     resources.setSrcDirs(listOf("$name/resources"))
 }
diff --git a/examples/kotlin-multiplatform/build.gradle b/examples/kotlin-multiplatform/build.gradle
index 3f916b89..c80cc595 100644
--- a/examples/kotlin-multiplatform/build.gradle
+++ b/examples/kotlin-multiplatform/build.gradle
@@ -4,7 +4,7 @@ import kotlinx.benchmark.gradle.JsBenchmarksExecutor
 
 plugins {
     id 'org.jetbrains.kotlin.multiplatform'
-    id 'org.jetbrains.kotlin.plugin.allopen' version "1.9.0"
+    id 'org.jetbrains.kotlin.plugin.allopen' version "1.9.21"
     id 'org.jetbrains.kotlinx.benchmark'
 }
 
@@ -28,7 +28,7 @@ kotlin {
     if (HostManager.hostIsLinux) linuxX64('native')
     if (HostManager.hostIsMingw) mingwX64('native')
 
-    sourceSets.all {
+    sourceSets.configureEach {
         languageSettings {
             progressiveMode = true
         }
diff --git a/examples/kotlin/build.gradle b/examples/kotlin/build.gradle
index 16916f5f..cd694936 100644
--- a/examples/kotlin/build.gradle
+++ b/examples/kotlin/build.gradle
@@ -1,7 +1,7 @@
 plugins {
     id 'java'
     id 'org.jetbrains.kotlin.jvm'
-    id 'org.jetbrains.kotlin.plugin.allopen' version "1.9.0"
+    id 'org.jetbrains.kotlin.plugin.allopen' version "1.9.21"
     id 'org.jetbrains.kotlinx.benchmark'
 }
 
@@ -16,7 +16,7 @@ sourceSets {
     benchmarks
 }
 
-sourceSets.all {
+sourceSets.configureEach {
     kotlin.srcDirs = ["$it.name/src"]
     java.srcDirs = ["$it.name/src"]
     resources.srcDirs = ["$it.name/resources"]
diff --git a/gradle.properties b/gradle.properties
index 67014227..9c731027 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -1,7 +1,7 @@
 group=org.jetbrains.kotlinx
 version=0.5.0-SNAPSHOT
 
-kotlin_version=1.9.0
+kotlin_version=1.9.21
 jmhVersion=1.21
 infra_version=0.3.0-dev-74
 kotlin.code.style=official
diff --git a/integration/src/main/kotlin/kotlinx/benchmark/integration/BenchmarkConfiguration.kt b/integration/src/main/kotlin/kotlinx/benchmark/integration/BenchmarkConfiguration.kt
index 2c66f336..3360994e 100644
--- a/integration/src/main/kotlin/kotlinx/benchmark/integration/BenchmarkConfiguration.kt
+++ b/integration/src/main/kotlin/kotlinx/benchmark/integration/BenchmarkConfiguration.kt
@@ -8,10 +8,10 @@ class BenchmarkConfiguration {
     var mode: String? = null
     var outputTimeUnit: String? = null
     var reportFormat: String? = null
-    var includes: MutableList<String> = mutableListOf()
-    var excludes: MutableList<String> = mutableListOf()
-    var params: MutableMap<String, MutableList<Any>> = mutableMapOf()
-    var advanced: MutableMap<String, Any> = mutableMapOf()
+    private var includes: MutableList<String> = mutableListOf()
+    private var excludes: MutableList<String> = mutableListOf()
+    private var params: MutableMap<String, MutableList<Any>> = mutableMapOf()
+    private var advanced: MutableMap<String, Any> = mutableMapOf()
 
     fun include(pattern: String) {
         includes.add(pattern)
@@ -41,7 +41,7 @@ class BenchmarkConfiguration {
             reportFormat = ${reportFormat?.escape()}
             includes = ${includes.map { it.escape() }}
             excludes = ${excludes.map { it.escape() }}
-            ${params.entries.joinToString(separator = "\n") { """param("${it.key}", ${it?.value?.joinToString()})""" }}
+            ${params.entries.joinToString(separator = "\n") { """param("${it.key}", ${it.value.joinToString()})""" }}
             ${advanced.entries.joinToString(separator = "\n") {
                 """advanced("${it.key}", ${if (it.value is String) "\"${it.value}\"" else it.value})"""
             }}
diff --git a/plugin/gradle.properties b/plugin/gradle.properties
index b9e1f9a8..285684db 100644
--- a/plugin/gradle.properties
+++ b/plugin/gradle.properties
@@ -1,7 +1,7 @@
 group=org.jetbrains.kotlinx
 version=0.5.0-SNAPSHOT
 
-kotlin_version=1.9.0
+kotlin_version=1.9.21
 jmhVersion=1.21
 infra_version=0.3.0-dev-74
 
diff --git a/plugin/main/src/kotlinx/benchmark/gradle/BenchmarksExtension.kt b/plugin/main/src/kotlinx/benchmark/gradle/BenchmarksExtension.kt
index 28c7f444..4bbfbd67 100644
--- a/plugin/main/src/kotlinx/benchmark/gradle/BenchmarksExtension.kt
+++ b/plugin/main/src/kotlinx/benchmark/gradle/BenchmarksExtension.kt
@@ -53,7 +53,7 @@ open class BenchmarksExtension(val project: Project) {
                     val target = multiplatform.targets.findByName(name)
                     // We allow the name to be either a target or a source set
                     when (val compilation = target?.compilations?.findByName(KotlinCompilation.MAIN_COMPILATION_NAME)
-                        ?: multiplatform.targets.flatMap { it.compilations }.find { it.defaultSourceSetName == name }) {
+                        ?: multiplatform.targets.flatMap { it.compilations }.find { it.defaultSourceSet.name == name }) {
                         null -> {
                             project.logger.warn("Warning: Cannot find a benchmark compilation '$name', ignoring.")
                             BenchmarkTarget(this, name) // ignore
diff --git a/plugin/main/src/kotlinx/benchmark/gradle/BenchmarksPlugin.kt b/plugin/main/src/kotlinx/benchmark/gradle/BenchmarksPlugin.kt
index c6edd059..f3798f0c 100644
--- a/plugin/main/src/kotlinx/benchmark/gradle/BenchmarksPlugin.kt
+++ b/plugin/main/src/kotlinx/benchmark/gradle/BenchmarksPlugin.kt
@@ -37,8 +37,8 @@ class BenchmarksPlugin : Plugin<Project> {
 
         plugins.withType(org.jetbrains.kotlin.gradle.plugin.KotlinBasePlugin::class.java) { kotlinPlugin ->
             logger.info("Detected Kotlin plugin version '${kotlinPlugin.pluginVersion}'")
-            if (!getKotlinVersion(kotlinPlugin.pluginVersion).isAtLeast(1, 9, 0)) {
-                logger.error("JetBrains Gradle Benchmarks plugin requires Kotlin version 1.9.0 or higher")
+            if (!getKotlinVersion(kotlinPlugin.pluginVersion).isAtLeast(1, 9, 20)) {
+                logger.error("JetBrains Gradle Benchmarks plugin requires Kotlin version 1.9.20 or higher")
             }
         }
 
diff --git a/plugin/main/src/kotlinx/benchmark/gradle/JsMultiplatformTasks.kt b/plugin/main/src/kotlinx/benchmark/gradle/JsMultiplatformTasks.kt
index c357bd2b..7d70e9bd 100644
--- a/plugin/main/src/kotlinx/benchmark/gradle/JsMultiplatformTasks.kt
+++ b/plugin/main/src/kotlinx/benchmark/gradle/JsMultiplatformTasks.kt
@@ -46,18 +46,20 @@ private fun Project.createJsBenchmarkCompileTask(target: JsBenchmarkTarget): Kot
             )
         }
 
-        compileKotlinTask.apply {
-            group = BenchmarksPlugin.BENCHMARKS_TASK_GROUP
-            description = "Compile JS benchmark source files for '${target.name}'"
+        compileTaskProvider.configure {
+            it.apply {
+                group = BenchmarksPlugin.BENCHMARKS_TASK_GROUP
+                description = "Compile JS benchmark source files for '${target.name}'"
 
-            //TODO: fix destination dir after KT-29711 is fixed
-            //println("JS: ${kotlinOptions.outputFile}")
-            //destinationDir = file("$benchmarkBuildDir/classes")
-            dependsOn("${target.name}${BenchmarksPlugin.BENCHMARK_GENERATE_SUFFIX}")
+                //TODO: fix destination dir after KT-29711 is fixed
+                //println("JS: ${kotlinOptions.outputFile}")
+                //destinationDir = file("$benchmarkBuildDir/classes")
+                dependsOn("${target.name}${BenchmarksPlugin.BENCHMARK_GENERATE_SUFFIX}")
 
-            kotlinOptions.apply {
-                sourceMap = true
-                moduleKind = "umd"
+                kotlinOptions.apply {
+                    sourceMap = true
+                    moduleKind = "umd"
+                }
             }
         }
     }
diff --git a/plugin/main/src/kotlinx/benchmark/gradle/NativeMultiplatformTasks.kt b/plugin/main/src/kotlinx/benchmark/gradle/NativeMultiplatformTasks.kt
index b9e3eaa7..301fb47d 100644
--- a/plugin/main/src/kotlinx/benchmark/gradle/NativeMultiplatformTasks.kt
+++ b/plugin/main/src/kotlinx/benchmark/gradle/NativeMultiplatformTasks.kt
@@ -62,7 +62,7 @@ private fun Project.createNativeBenchmarkCompileTask(target: NativeBenchmarkTarg
     // a link task. So we disable execution the klib compiling task to save time.
 //    benchmarkCompilation.compileKotlinTask.enabled = false
 
-    benchmarkCompilation.compileKotlinTask.dependsOn(generateSourceTaskName(target))
+    benchmarkCompilation.compileTaskProvider.configure { it.dependsOn(generateSourceTaskName(target)) }
 
     benchmarkCompilation.apply {
         val sourceSet = kotlinSourceSets.single()
diff --git a/plugin/main/src/kotlinx/benchmark/gradle/WasmMultiplatformTasks.kt b/plugin/main/src/kotlinx/benchmark/gradle/WasmMultiplatformTasks.kt
index 117646d7..8308e877 100644
--- a/plugin/main/src/kotlinx/benchmark/gradle/WasmMultiplatformTasks.kt
+++ b/plugin/main/src/kotlinx/benchmark/gradle/WasmMultiplatformTasks.kt
@@ -42,10 +42,12 @@ private fun Project.createWasmBenchmarkCompileTask(target: WasmBenchmarkTarget):
                 )
             }
         }
-        compileKotlinTask.apply {
-            group = BenchmarksPlugin.BENCHMARKS_TASK_GROUP
-            description = "Compile Wasm benchmark source files for '${target.name}'"
-            dependsOn("${target.name}${BenchmarksPlugin.BENCHMARK_GENERATE_SUFFIX}")
+        compileTaskProvider.configure {
+            it.apply {
+                group = BenchmarksPlugin.BENCHMARKS_TASK_GROUP
+                description = "Compile Wasm benchmark source files for '${target.name}'"
+                dependsOn("${target.name}${BenchmarksPlugin.BENCHMARK_GENERATE_SUFFIX}")
+            }
         }
     }
     return benchmarkCompilation
diff --git a/runtime/build.gradle b/runtime/build.gradle
index f2b980d0..32e0cecf 100644
--- a/runtime/build.gradle
+++ b/runtime/build.gradle
@@ -51,7 +51,13 @@ kotlin {
     js("jsIr", IR) { nodejs() }
     wasm("wasmJs") { d8() }
 
-    sourceSets.all {
+    targets.configureEach {
+        compilations.configureEach {
+            kotlinOptions.freeCompilerArgs += "-Xexpect-actual-classes"
+        }
+    }
+
+    sourceSets.configureEach {
         kotlin.srcDirs = ["$it.name/src"]
         resources.srcDirs = ["$it.name/resources"]
         languageSettings {
diff --git a/runtime/jsMain/src/kotlinx/benchmark/JsBenchmarkAnnotations.kt b/runtime/jsMain/src/kotlinx/benchmark/JsBenchmarkAnnotations.kt
index 6ba95b2d..2c17e109 100644
--- a/runtime/jsMain/src/kotlinx/benchmark/JsBenchmarkAnnotations.kt
+++ b/runtime/jsMain/src/kotlinx/benchmark/JsBenchmarkAnnotations.kt
@@ -4,9 +4,16 @@ actual enum class Scope {
     Benchmark
 }
 
+@Target(AnnotationTarget.CLASS)
 actual annotation class State(actual val value: Scope)
+
+@Target(AnnotationTarget.FUNCTION)
 actual annotation class Setup
+
+@Target(AnnotationTarget.FUNCTION)
 actual annotation class TearDown
+
+@Target(AnnotationTarget.FUNCTION)
 actual annotation class Benchmark
 
 
diff --git a/runtime/nativeMain/src/kotlinx/benchmark/NativeBenchmarkAnnotations.kt b/runtime/nativeMain/src/kotlinx/benchmark/NativeBenchmarkAnnotations.kt
index 11615a39..2b680f9d 100644
--- a/runtime/nativeMain/src/kotlinx/benchmark/NativeBenchmarkAnnotations.kt
+++ b/runtime/nativeMain/src/kotlinx/benchmark/NativeBenchmarkAnnotations.kt
@@ -4,9 +4,16 @@ actual enum class Scope {
     Benchmark
 }
 
+@Target(AnnotationTarget.CLASS)
 actual annotation class State(actual val value: Scope)
+
+@Target(AnnotationTarget.FUNCTION)
 actual annotation class Setup
+
+@Target(AnnotationTarget.FUNCTION)
 actual annotation class TearDown
+
+@Target(AnnotationTarget.FUNCTION)
 actual annotation class Benchmark
 
 
diff --git a/runtime/wasmJsMain/src/kotlinx/benchmark/WasmBenchmarkAnnotations.kt b/runtime/wasmJsMain/src/kotlinx/benchmark/WasmBenchmarkAnnotations.kt
index 6ba95b2d..2c17e109 100644
--- a/runtime/wasmJsMain/src/kotlinx/benchmark/WasmBenchmarkAnnotations.kt
+++ b/runtime/wasmJsMain/src/kotlinx/benchmark/WasmBenchmarkAnnotations.kt
@@ -4,9 +4,16 @@ actual enum class Scope {
     Benchmark
 }
 
+@Target(AnnotationTarget.CLASS)
 actual annotation class State(actual val value: Scope)
+
+@Target(AnnotationTarget.FUNCTION)
 actual annotation class Setup
+
+@Target(AnnotationTarget.FUNCTION)
 actual annotation class TearDown
+
+@Target(AnnotationTarget.FUNCTION)
 actual annotation class Benchmark