diff --git a/build-logic/src/main/kotlin/ktorbuild.kmp.gradle.kts b/build-logic/src/main/kotlin/ktorbuild.kmp.gradle.kts
index 6cc6088435..5966eca2a9 100644
--- a/build-logic/src/main/kotlin/ktorbuild.kmp.gradle.kts
+++ b/build-logic/src/main/kotlin/ktorbuild.kmp.gradle.kts
@@ -2,6 +2,8 @@
  * Copyright 2014-2024 JetBrains s.r.o and contributors. Use of this source code is governed by the Apache 2.0 license.
  */
 
+@file:OptIn(ExperimentalKotlinGradlePluginApi::class)
+
 import ktorbuild.internal.gradle.*
 import ktorbuild.internal.ktorBuild
 import ktorbuild.maybeNamed
@@ -14,7 +16,13 @@ plugins {
 }
 
 kotlin {
-    @OptIn(ExperimentalKotlinGradlePluginApi::class)
+    compilerOptions {
+        progressiveMode = true
+        apiVersion = ktorBuild.kotlinApiVersion
+        languageVersion = ktorBuild.kotlinLanguageVersion
+        freeCompilerArgs.addAll("-Xexpect-actual-classes")
+    }
+
     applyHierarchyTemplate(KtorTargets.hierarchyTemplate)
     addTargets(ktorBuild.targets)
 
diff --git a/build-logic/src/main/kotlin/ktorbuild/KtorBuildExtension.kt b/build-logic/src/main/kotlin/ktorbuild/KtorBuildExtension.kt
index b8bd8063fd..ca2d2eb5a5 100644
--- a/build-logic/src/main/kotlin/ktorbuild/KtorBuildExtension.kt
+++ b/build-logic/src/main/kotlin/ktorbuild/KtorBuildExtension.kt
@@ -16,6 +16,7 @@ import org.gradle.kotlin.dsl.newInstance
 import org.gradle.kotlin.dsl.property
 import org.gradle.platform.BuildPlatform
 import org.gradle.platform.OperatingSystem
+import org.jetbrains.kotlin.gradle.dsl.KotlinVersion
 import javax.inject.Inject
 
 @Suppress("UnstableApiUsage")
@@ -69,6 +70,26 @@ abstract class KtorBuildExtension(
             .orElse(providers.provider { JavaVersion.current().majorVersion })
             .map(JavaLanguageVersion::of)
 
+    /**
+     * The Kotlin API version Ktor should be compatible with.
+     *
+     * DON'T change the property name as it is used in Kotlin Libraries train.
+     */
+    val kotlinApiVersion: Provider<KotlinVersion> =
+        providers.gradleProperty("kotlin_api_version")
+            .map(KotlinVersion::fromVersion)
+            .orElse(DEFAULT_KOTLIN_VERSION)
+
+    /**
+     * The Kotlin Language version Ktor should be compatible with.
+     *
+     * DON'T change the property name as it is used in Kotlin Libraries train.
+     */
+    val kotlinLanguageVersion: Provider<KotlinVersion> =
+        providers.gradleProperty("kotlin_language_version")
+            .map(KotlinVersion::fromVersion)
+            .orElse(DEFAULT_KOTLIN_VERSION)
+
     /** Host operating system. */
     val os: Provider<OperatingSystem> = providers.provider { buildPlatform.operatingSystem }
 
@@ -77,5 +98,8 @@ abstract class KtorBuildExtension(
 
         /** The default (minimal) JDK version used for building the project. */
         private val DEFAULT_JDK = JavaLanguageVersion.of(8)
+
+        /** The default (minimal) Kotlin version used as API and Language version. */
+        private val DEFAULT_KOTLIN_VERSION = KotlinVersion.KOTLIN_2_0
     }
 }
diff --git a/build.gradle.kts b/build.gradle.kts
index 67fad57523..ce38f4cbe0 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -2,7 +2,6 @@
  * Copyright 2014-2024 JetBrains s.r.o and contributors. Use of this source code is governed by the Apache 2.0 license.
  */
 
-import org.jetbrains.kotlin.gradle.tasks.KotlinCompilationTask
 import org.jetbrains.kotlin.konan.target.HostManager
 
 extra["globalM2"] = "${project.file("build")}/m2"
@@ -61,12 +60,6 @@ subprojects {
 
     kotlin {
         if (!disabledExplicitApiModeProjects.contains(project.name)) explicitApi()
-
-        compilerOptions {
-            languageVersion = getKotlinLanguageVersion()
-            apiVersion = getKotlinApiVersion()
-            progressiveMode = true
-        }
     }
 
     val skipPublish: List<String> by rootProject.extra
@@ -91,9 +84,3 @@ fun configureDokka() {
 }
 
 configureDokka()
-
-subprojects {
-    tasks.withType<KotlinCompilationTask<*>>().configureEach {
-        configureCompilerOptions()
-    }
-}
diff --git a/buildSrc/src/main/kotlin/Compilations.kt b/buildSrc/src/main/kotlin/Compilations.kt
deleted file mode 100644
index 5befd7687e..0000000000
--- a/buildSrc/src/main/kotlin/Compilations.kt
+++ /dev/null
@@ -1,12 +0,0 @@
-/*
- * Copyright 2014-2024 JetBrains s.r.o and contributors. Use of this source code is governed by the Apache 2.0 license.
- */
-
-import org.jetbrains.kotlin.gradle.tasks.*
-
-fun KotlinCompilationTask<*>.configureCompilerOptions() {
-    compilerOptions {
-        progressiveMode.set(true)
-        freeCompilerArgs.addAll("-Xexpect-actual-classes")
-    }
-}
diff --git a/buildSrc/src/main/kotlin/Train.kt b/buildSrc/src/main/kotlin/Train.kt
index 3b3d4698ea..a91a830f33 100644
--- a/buildSrc/src/main/kotlin/Train.kt
+++ b/buildSrc/src/main/kotlin/Train.kt
@@ -1,12 +1,11 @@
 /*
  * Copyright 2014-2024 JetBrains s.r.o and contributors. Use of this source code is governed by the Apache 2.0 license.
  */
-import internal.*
-import org.gradle.api.*
-import org.gradle.api.provider.*
-import org.gradle.api.tasks.testing.*
-import org.gradle.kotlin.dsl.*
-import org.jetbrains.kotlin.gradle.dsl.*
+import internal.libs
+import org.gradle.api.Project
+import org.gradle.api.provider.Provider
+import org.gradle.api.tasks.testing.Test
+import org.gradle.kotlin.dsl.withType
 
 fun Project.filterSnapshotTests() {
     if (!buildSnapshotTrain) return
@@ -67,31 +66,3 @@ private fun check(version: Any, libVersionProvider: Provider<String>, libName: S
         "Current deploy version is $version, but $libName version is not overridden ($libVersion)"
     }
 }
-
-private var resolvedKotlinApiVersion: KotlinVersion? = null
-
-fun Project.getKotlinApiVersion(): KotlinVersion =
-    resolvedKotlinApiVersion ?: resolveKotlinApiVersion().also { resolvedKotlinApiVersion = it }
-
-private fun Project.resolveKotlinApiVersion(): KotlinVersion {
-    val apiVersion = rootProject.findProperty("kotlin_api_version")
-        ?.let { KotlinVersion.fromVersion(it.toString()) }
-        ?: KotlinVersion.KOTLIN_2_0
-    logger.info("Kotlin API version: $apiVersion")
-
-    return apiVersion
-}
-
-private var resolvedKotlinLanguageVersion: KotlinVersion? = null
-
-fun Project.getKotlinLanguageVersion(): KotlinVersion =
-    resolvedKotlinLanguageVersion ?: resolveKotlinLanguageVersion().also { resolvedKotlinLanguageVersion = it }
-
-private fun Project.resolveKotlinLanguageVersion(): KotlinVersion {
-    val languageVersion = rootProject.findProperty("kotlin_language_version")
-        ?.let { KotlinVersion.fromVersion(it.toString()) }
-        ?: KotlinVersion.KOTLIN_2_0
-    logger.info("Kotlin language version: $languageVersion")
-
-    return languageVersion
-}