Kotlin Multiplatform Gradle Sync Fails in CI

A Kotlin Multiplatform Gradle build failed to configure. The Kotlin Gradle plugin and Android Gradle Plugin versions are out of step, a target platform is misconfigured, or a native/expect-actual dependency could not be resolved.

What this error means

Gradle fails during configuration of a KMP module - a Kotlin/AGP compatibility error, a missing androidTarget()/iosX64() target, or an unresolved klib. The message points at the Kotlin plugin or a specific target.

Gradle output

> The Android Gradle plugin supports only Kotlin Gradle plugin version 1.9.20 and higher.
# or
> Cannot locate tasks that match ':shared:compileKotlinIosArm64' as task 'compileKotlinIosArm64' not found

Common causes

Kotlin / AGP / Gradle version mismatch

KMP is sensitive to the Kotlin Gradle plugin, AGP, and Gradle versions lining up. A mismatch fails at configuration time.

A target not configured for this build

A task references a platform target (e.g. iosArm64) that the kotlin { } block does not declare, so Gradle cannot find it.

How to fix it

Align the Kotlin/AGP/Gradle versions

Use a compatible matrix in your version catalog and the Gradle wrapper.

libs.versions.toml

# gradle/libs.versions.toml
[versions]
kotlin = "2.0.20"
agp = "8.5.2"
# ensure gradle/wrapper/gradle-wrapper.properties uses a Gradle that supports both

Declare every target you build

Make sure the kotlin { } block declares the platforms your tasks compile.

build.gradle.kts

kotlin {
  androidTarget()
  iosArm64()
  iosSimulatorArm64()
}

How to prevent it

Manage Kotlin/AGP versions in a single version catalog.
Pin the Gradle wrapper to a version compatible with your Kotlin/AGP.
Declare all platform targets your CI tasks compile.