How to Fix Version Mismatch in Kotlin

Version Mismatch in Kotlin

Kotlin version mismatches arise between the Kotlin compiler, Kotlin stdlib, and libraries compiled with different Kotlin versions. This causes IncompatibleClassChangeError or metadata errors.

Why It Happens

• Kotlin compiler version differs from stdlib version
• Libraries compiled with newer Kotlin than your project
• Gradle plugin version not matching Kotlin version

Fix

Align Kotlin versions across your build:

// build.gradle.kts
plugins {
    kotlin("jvm") version "1.9.22"
    kotlin("plugin.spring") version "1.9.22"
}

dependencies {
    // Use the Kotlin BOM for version alignment
    implementation(platform("org.jetbrains.kotlin:kotlin-bom:1.9.22"))
    implementation("org.jetbrains.kotlin:kotlin-stdlib")
    implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core:1.7.3")
}

kotlin {
    jvmToolchain(17)
}

Use the Kotlin BOM to ensure all Kotlin libraries use the same version, and always update the compiler and stdlib together.

Best Practices

Defensive coding prevents most instances of this error. Validate all inputs at system boundaries, set reasonable defaults, and log enough context to diagnose issues without exposing sensitive data. Code reviews should specifically check for unhandled edge cases around this error type.

Bugsly for Kotlin

Bugsly detects Kotlin metadata version errors and IncompatibleClassChangeError at runtime, showing which library was compiled with an incompatible Kotlin version.

Remember to test your fix across all environments — development, staging, and production — since configuration differences often cause this error to reappear. Keeping dependencies updated and monitoring error trends will help you stay ahead of similar issues.