Your project requires a newer version of the Kotlin Gradle plugin. (Android Studio)

Question

I've just updated my flutter project packages to be null-safety compliant and now Android Studio wants me to update my project to use the latest version of Kotling Gradle Plugin. Can't see where to change this though. I have tried to change "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version" into "org.jetbrains.kotlin:kotlin-stdlib-jdk7:1.6.10" but this has no effect.

My build.grade-file looks like this:

def localProperties = new Properties()
def localPropertiesFile = rootProject.file('local.properties')
if (localPropertiesFile.exists()) {
    localPropertiesFile.withReader('UTF-8') { reader ->
        localProperties.load(reader)
    }
}

def flutterRoot = localProperties.getProperty('flutter.sdk')
if (flutterRoot == null) {
    throw new GradleException("Flutter SDK not found. Define location with flutter.sdk in the local.properties file.")
}

def flutterVersionCode = localProperties.getProperty('flutter.versionCode')
if (flutterVersionCode == null) {
    flutterVersionCode = '1'
}

def flutterVersionName = localProperties.getProperty('flutter.versionName')
if (flutterVersionName == null) {
    flutterVersionName = '1.0'
}

apply plugin: 'com.android.application'
apply plugin: 'kotlin-android'
apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"

def keystoreProperties = new Properties()
def keystorePropertiesFile = rootProject.file('key.properties')
if (keystorePropertiesFile.exists()) {
    keystoreProperties.load(new FileInputStream(keystorePropertiesFile))
}

android {
    compileSdkVersion 31

    sourceSets {
        main.java.srcDirs += 'src/main/kotlin'
    }

    lintOptions {
        disable 'InvalidPackage'
    }

    defaultConfig {
        // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
        applicationId "*********"
        minSdkVersion 30
        targetSdkVersion 30
        versionCode flutterVersionCode.toInteger()
        versionName flutterVersionName
        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }



    signingConfigs {
        release {
            keyAlias keystoreProperties['keyAlias']
            keyPassword keystoreProperties['keyPassword']
            storeFile keystoreProperties['storeFile'] ? file(keystoreProperties['storeFile']) : null
            storePassword keystoreProperties['storePassword']
        }
    }
    buildTypes {
        release {
            signingConfig signingConfigs.release
        }
    }

}

flutter {
    source '../..'
}

dependencies {
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'androidx.test:runner:1.1.1'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.1.1'
    implementation 'com.google.firebase:firebase-analytics:17.2.2'
}
apply plugin: 'com.google.gms.google-services'

Build output:

BUILD FAILED in 8s
[!] Your project requires a newer version of the Kotlin Gradle plugin.
    Find the latest version on https://kotlinlang.org/docs/gradle.html#plugin-and-versions, then update project/android/build.gradle:
    ext.kotlin_version = '<latest-version>'
Exception: Gradle task assembleDebug failed with exit code 1

Answer 1

You need to change the kotlin version in your android root project, projectName/android/build.gradle, instead of projectName/android/app/build.gradle.

Change the version at ext.kotlin_version line:

buildscript {
    ext.kotlin_version = '1.6.10' // Change here
    repositories {
        google()
        jcenter()
    }

    dependencies {
        classpath 'com.android.tools.build:gradle:4.1.0'
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
    }
}

---

UPDATE

The above solution will also works if your android part of the project is using java where the dependencies are using kotlin and you've encountered the following error:

Incompatible classes were found in dependencies. Remove them from the classpath or use '-Xskip-metadata-version-check' to suppress errors
e: /home/user/.gradle/caches/transforms-3/36814238b86d8b6b6f9e4e1263bce879/transformed/jetified-kotlinx-coroutines-core-jvm-1.5.2.jar!/META-INF/kotlinx-coroutines-core.kotlin_module: 
Module was compiled with an incompatible version of Kotlin. 
The binary version of its metadata is 1.5.1, expected version is 1.1.15.

AndroidStudio or IntelliJ Idea will give hint in the project build.gradle file if the kotlin is not the same with the installed kotlin in the IDE.

Note: to see the new versions of Kotlin check this link : https://kotlinlang.org/docs/releases.html#release-details