diff --git a/README.md b/README.md
index e97a643..9001c48 100644
--- a/README.md
+++ b/README.md
@@ -11,7 +11,33 @@ The Approov integration is available via [`maven`](https://mvnrepository.com/rep
 The `Maven` repository is already present in the gradle.build file so the only import you need to make is the actual service layer itself:
 
 ```
-implementation("io.approov:service.httpsurlconn:3.5.3")
+implementation("io.approov:service.httpsurlconn:3.5.4")
+```
+
+The service layer requires [core library desugaring](https://developer.android.com/studio/write/java8-support#library-desugaring) and a minimum SDK version of 23. Add the following to the app-level `build.gradle` file:
+
+```
+android {
+    defaultConfig {
+        minSdkVersion 23
+    }
+    compileOptions {
+        coreLibraryDesugaringEnabled true
+    }
+}
+
+dependencies {
+    coreLibraryDesugaring 'com.android.tools:desugar_jdk_libs:2.1.4'
+}
+```
+
+Use Android Gradle plugin 8.x or later. With Android Gradle plugin 7.x, the build fails in D8 with a `NullPointerException` while it processes the service layer. With Android Gradle plugin 8.x and no desugaring, the build fails with `Dependency 'io.approov:service.httpsurlconn:3.5.4' requires core library desugaring to be enabled`.
+
+If your release build uses R8 (`minifyEnabled true`), add these rules to your ProGuard rules file. The Approov SDK refers to optional Google Play services and Play Integrity classes, and Android Gradle plugin 8 stops the build with `Missing class` errors if they are not present:
+
+```
+-dontwarn com.google.android.gms.tasks.**
+-dontwarn com.google.android.play.core.integrity.**
 ```
 
 Make sure you do a Gradle sync (by selecting `Sync Now` in the banner at the top of the modified `.gradle` file) after making these changes.
@@ -26,7 +52,7 @@ The following app permissions need to be available in the manifest to use Approo
 <uses-permission android:name="android.permission.INTERNET" />
 ```
 
-Note that the minimum SDK version you can use with the Approov package is 21 (Android 5.0). 
+Note that the minimum SDK version you can use with the Approov package is 23 (Android 6.0). 
 
 Please [read this](https://approov.io/docs/latest/approov-usage-documentation/#targeting-android-11-and-above) section of the reference documentation if targeting Android 11 (API level 30) or above.
 
diff --git a/SHAPES-EXAMPLE.md b/SHAPES-EXAMPLE.md
index ead6c8a..bf10408 100644
--- a/SHAPES-EXAMPLE.md
+++ b/SHAPES-EXAMPLE.md
@@ -5,7 +5,7 @@ This quickstart is written specifically for native Android apps that are written
 ## WHAT YOU WILL NEED
 * Access to a trial or paid Approov account
 * The `approov` command line tool [installed](https://approov.io/docs/latest/approov-installation/) with access to your account
-* [Android Studio](https://developer.android.com/studio) installed (Android Studio Bumblebee 2021.1.1 is used in this guide)
+* [Android Studio](https://developer.android.com/studio) installed, in a version that supports Android Gradle plugin 8.9 (see the [compatibility table](https://developer.android.com/build/releases/gradle-plugin#android_gradle_plugin_and_android_studio_compatibility)). The Shapes app uses Android Gradle plugin 8.9.0 and Gradle 8.11.1, which require JDK 17.
 * The contents of this repo
 
 ## RUNNING THE SHAPES APP WITHOUT APPROOV
@@ -45,9 +45,11 @@ The `approov-service-httpsurlconn` dependency needs to be added as follows to th
 ![App Build Gradle](readme-images/app-gradle.png)
 
 ```
-implementation("io.approov:service.httpsurlconn:3.5.3")
+implementation("io.approov:service.httpsurlconn:3.5.4")
 ```
 
+The service layer requires [core library desugaring](https://developer.android.com/studio/write/java8-support#library-desugaring) and a minimum SDK version of 23. The Shapes app already sets `minSdkVersion 23`, `coreLibraryDesugaringEnabled true` and the `coreLibraryDesugaring 'com.android.tools:desugar_jdk_libs:2.1.4'` dependency in `app/build.gradle`, so no other change is necessary. If you add Approov to your own app, see [ADDING APPROOV SERVICE DEPENDENCY](README.md#adding-approov-service-dependency).
+
 Make sure you do a Gradle sync (by selecting `Sync Now` in the banner at the top of the modified `.gradle` file) after making these changes.
 
 Note that `approov-service-httpsurlconn` is actually an open source wrapper layer that allows you to easily use Approov with `HttpsUrlConnection`. This has a further dependency to the closed source Approov SDK itself.
diff --git a/shapes-app/app/build.gradle b/shapes-app/app/build.gradle
index 1f496e7..d3690b4 100644
--- a/shapes-app/app/build.gradle
+++ b/shapes-app/app/build.gradle
@@ -1,11 +1,12 @@
 apply plugin: 'com.android.application'
 
 android {
-    compileSdkVersion 31
+    namespace "io.approov.shapes"
+    compileSdkVersion 35
     defaultConfig {
         applicationId "io.approov.shapes"
-        minSdkVersion 21
-        targetSdkVersion 31
+        minSdkVersion 23
+        targetSdkVersion 34
         versionCode  3
         versionName "3.0"
     }
@@ -27,11 +28,14 @@ android {
         compileOptions {
             sourceCompatibility JavaVersion.VERSION_1_8
             targetCompatibility JavaVersion.VERSION_1_8
+            // Required by io.approov:service.httpsurlconn 3.5.4 and later
+            coreLibraryDesugaringEnabled true
         }
     }
 }
 
 dependencies {
+    coreLibraryDesugaring 'com.android.tools:desugar_jdk_libs:2.1.4'
     implementation fileTree(dir: 'libs', include: ['*.jar'])
     implementation 'androidx.appcompat:appcompat:1.4.1'
 }
diff --git a/shapes-app/app/proguard-rules.pro b/shapes-app/app/proguard-rules.pro
index f185b4d..5f35773 100644
--- a/shapes-app/app/proguard-rules.pro
+++ b/shapes-app/app/proguard-rules.pro
@@ -16,3 +16,9 @@
 #   public *;
 #}
 -keep class com.criticalblue.approovsdk.** {*;}
+
+# The Approov SDK refers to optional Google Play services and Play Integrity classes that
+# are not present unless the app includes those libraries. Android Gradle plugin 8 treats
+# missing classes as an error in R8.
+-dontwarn com.google.android.gms.tasks.**
+-dontwarn com.google.android.play.core.integrity.**
diff --git a/shapes-app/app/src/main/AndroidManifest.xml b/shapes-app/app/src/main/AndroidManifest.xml
index 4780fdd..3b66e07 100644
--- a/shapes-app/app/src/main/AndroidManifest.xml
+++ b/shapes-app/app/src/main/AndroidManifest.xml
@@ -1,6 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
-<manifest xmlns:android="http://schemas.android.com/apk/res/android"
-    package="io.approov.shapes">
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
 
     <uses-permission android:name="android.permission.INTERNET" />
     <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
diff --git a/shapes-app/build.gradle b/shapes-app/build.gradle
index 8fb329d..8d721f0 100644
--- a/shapes-app/build.gradle
+++ b/shapes-app/build.gradle
@@ -8,7 +8,7 @@ buildscript {
         mavenCentral()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:7.1.1'
+        classpath 'com.android.tools.build:gradle:8.9.0'
         // NOTE: Do not place your application dependencies here; they belong
         // in the individual module build.gradle files
     }
diff --git a/shapes-app/gradle/wrapper/gradle-wrapper.properties b/shapes-app/gradle/wrapper/gradle-wrapper.properties
index 63deabe..31dc497 100644
--- a/shapes-app/gradle/wrapper/gradle-wrapper.properties
+++ b/shapes-app/gradle/wrapper/gradle-wrapper.properties
@@ -3,4 +3,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.11.1-bin.zip