How to Fix Core Library Desugaring and Java Version Warnings After Upgrading to Flutter 3.27.3

Ayesha Iftikhar
3 min readFeb 3, 2025

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After upgrading to Flutter 3.27.3, developers may encounter errors related to core library desugaring and Java version compatibility while building APKs or app bundles. This article provides a step-by-step guide to resolve these issues, including enabling core library desugaring, updating Java version settings, and modifying Gradle configurations to ensure a smooth build process.

Dependency ‘:flutter_local_notifications’ requires core library desugaring to be enabled for :app.

Here how, you can fix it quickly:

Add the following in android>app>build.grable :

compileOptions {
...
coreLibraryDesugaringEnabled true
}
dependencies {
implementation 'androidx.window:window:1.0.0'
implementation 'androidx.window:window-java:1.0.0'
coreLibraryDesugaring 'com.android.tools:desugar_jdk_libs:2.0.3'
}

If you have recently upgraded your Java version to 21, you might be getting these following warnings:

To fix or remove this warning you might need to change the following files:

  • In android/app/build.gradle :
// change
compileOptions {
sourceCompatibility = JavaVersion.VERSION_1_8
targetCompatibility = JavaVersion.VERSION_1_8
}
kotlinOptions {
jvmTarget = JavaVersion.VERSION_1_8
}
// to
compileOptions {
sourceCompatibility = JavaVersion.VERSION_17
targetCompatibility = JavaVersion.VERSION_17
}
kotlinOptions {
jvmTarget = JavaVersion.VERSION_17
}

In gradle/wrapper/gradle-wrapper.properties change your distributionUrl to the following:

distributionUrl=https\://services.gradle.org/distributions/gradle-8.10.2-all.zip

In some cases, you might want to update com.android.application in android/setting.gradle file.

id "com.android.application" version "8.5.0" apply false

Conclusion:
Upgrading to Flutter 3.27.3 can introduce challenges related to core library desugaring and Java version compatibility, but these issues can be resolved with a few adjustments to your project’s configuration files. By enabling core library desugaring, updating the Java version settings, and ensuring your Gradle configurations are up-to-date, you can eliminate build errors and warnings. Following these steps will help you maintain a seamless development workflow and keep your Flutter projects running smoothly.

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Ayesha Iftikhar
Ayesha Iftikhar

Written by Ayesha Iftikhar

I am professional software engineer with experience of around 4 years in Mobile Application Development using Flutter and overall 5 years of experience in IT.

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