Starting from Expo SDK 49 (React Native 0.72), the React Native Android project uses Gradle 8 as the default version. If your project includes custom Expo Modules, you might encounter build errors or warnings related to this change. This migration guide provides step-by-step instructions to resolve any issues and ensure Gradle 8 compatibility.

If you encounter an error similar to the following:

* What went wrong:
A problem occurred evaluating project ':tester'.
> Could not set unknown property 'classifier' for task ':tester:androidSourcesJar' of type org.gradle.api.tasks.bundling.Jar.

You can apply the following patch to your module's build.gradle file to resolve the issue:

--- a/modules/tester/android/build.gradle
+++ b/modules/tester/android/build.gradle
@@ -35,19 +35,11 @@ buildscript {
   }
 }

-// Creating sources with comments
-task androidSourcesJar(type: Jar) {
-  classifier = 'sources'
-  from android.sourceSets.main.java.srcDirs
-}
-
 afterEvaluate {
   publishing {
     publications {
       release(MavenPublication) {
         from components.release
-        // Add additional sourcesJar to artifacts
-        artifact(androidSourcesJar)
       }
     }
   }
 }
 
 android {
   lintOptions {
     abortOnError false
   }
+  publishing {
+    singleVariant("release") {
+      withSourcesJar()
+    }
+  }
 }

 repositories {

When upgrading Expo SDK 50 from your existing Android project, you may get a similar error:

> 'compileReleaseJavaWithJavac' task (current target is 17) and 'compileReleaseKotlin' task (current target is 11) jvm target compatibility should be set to the same Java version.
  Consider using JVM toolchain: https://kotl.in/gradle/jvm/toolchain

Since Expo SDK 50 or React Native 0.73, the JVM target version will be setup by @react-native/gradle-plugin and JVM toolchain. You can remove the previous JVM target version in your library's build.gradle:

--- a/android/build.gradle
+++ b/android/build.gradle
@@ -53,13 +53,16 @@ afterEvaluate {
 android {
   compileSdkVersion safeExtGet("compileSdkVersion", 34)
 
-  compileOptions {
-    sourceCompatibility JavaVersion.VERSION_11
-    targetCompatibility JavaVersion.VERSION_11
-  }
+  def agpVersion = com.android.Version.ANDROID_GRADLE_PLUGIN_VERSION
+  if (agpVersion.tokenize('.')[0].toInteger() < 8) {
+    compileOptions {
+      sourceCompatibility JavaVersion.VERSION_11
+      targetCompatibility JavaVersion.VERSION_11
+    }
 
-  kotlinOptions {
-    jvmTarget = JavaVersion.VERSION_11.majorVersion
+    kotlinOptions {
+      jvmTarget = JavaVersion.VERSION_11.majorVersion
+    }
   }

If you see a warning similar to the following:

package="com.tester" found in source AndroidManifest.xml: /path/to/modules/tester/android/src/main/AndroidManifest.xml.
Setting the namespace via a source AndroidManifest.xml's package attribute is deprecated.
Please instead set the namespace (or testNamespace) in the module's build.gradle file, as described here: https://developer.android.com/studio/build/configure-app-module#set-namespace
This migration can be done automatically using the AGP Upgrade Assistant, please refer to https://developer.android.com/studio/build/agp-upgrade-assistant for more information.

Please note that this warning will become an error starting from React Native 0.73. To address the issue in advance, you can follow these steps:

1. Open your module's build.gradle file.

2. Locate the android block and add the following line:

   --- a/modules/tester/android/build.gradle
   +++ b/modules/tester/android/build.gradle
   @@ -59,6 +51,7 @@ afterEvaluate {
   }
   
   android {
   +  namespace = "com.tester"
      compileSdkVersion safeExtGet("compileSdkVersion", 33)
   
      compileOptions {

3. Open your module's AndroidManifest.xml file.

4. Replace the package attribute with namespace, as shown in the following patch:

   --- a/modules/tester/android/src/main/AndroidManifest.xml
   +++ b/modules/tester/android/src/main/AndroidManifest.xml
   @@ -1,2 +1,2 @@
   -<manifest package="com.tester">
   +<manifest>
    </manifest>

By following these steps, you will address the deprecation warning and ensure compatibility with Gradle 8.