diff --git a/app/build.gradle b/app/build.gradle
index 425f097..019e018 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -4,7 +4,7 @@ group = 'com.artifex.mupdf'
 version = '1.19.0'
 
 dependencies {
-	implementation 'androidx.appcompat:appcompat:1.1.+'
+	implementation 'androidx.appcompat:appcompat:1.4.1'
 	if (file('../lib/build.gradle').isFile())
 		api project(':lib')
 	else
@@ -12,10 +12,10 @@ dependencies {
 }
 
 android {
-	compileSdkVersion 28
+	compileSdkVersion 31
 	defaultConfig {
 		minSdkVersion 16
-		targetSdkVersion 28
+		targetSdkVersion 31
 		versionName '1.19.0'
 		versionCode 100
 	}
@@ -48,4 +48,9 @@ android {
 			}
 		}
 	}
+
+	compileOptions {
+		sourceCompatibility JavaVersion.VERSION_1_8
+		targetCompatibility JavaVersion.VERSION_1_8
+	}
 }
diff --git a/app/src/main/AndroidManifest.xml b/app/src/main/AndroidManifest.xml
index 00ab9ce..a314245 100644
--- a/app/src/main/AndroidManifest.xml
+++ b/app/src/main/AndroidManifest.xml
@@ -1,23 +1,21 @@
 <?xml version="1.0" encoding="utf-8"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
-	package="com.artifex.mupdf.viewer.app"
-	android:installLocation="auto"
-	>
-	<uses-permission
-		android:name="android.permission.READ_EXTERNAL_STORAGE"
-		/>
-	<application
-		android:label="MuPDF viewer"
-		android:icon="@drawable/ic_mupdf"
-		>
-		<activity
-			android:name=".LibraryActivity"
-			android:configChanges="orientation|screenSize|keyboardHidden"
-			>
-			<intent-filter>
-				<action android:name="android.intent.action.MAIN" />
-				<category android:name="android.intent.category.LAUNCHER" />
-			</intent-filter>
-		</activity>
-	</application>
+    package="com.artifex.mupdf.viewer.app"
+    android:installLocation="auto">
+
+    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
+    <application
+        android:allowBackup="false"
+        android:icon="@drawable/ic_mupdf"
+        android:label="MuPDF viewer">
+        <activity
+            android:name=".LibraryActivity"
+            android:configChanges="orientation|screenSize|keyboardHidden"
+            android:exported="true">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+    </application>
 </manifest>
diff --git a/build.gradle b/build.gradle
index a9f422d..eec7898 100644
--- a/build.gradle
+++ b/build.gradle
@@ -4,7 +4,7 @@ buildscript {
 		google()
 	}
 	dependencies {
-		classpath 'com.android.tools.build:gradle:3.5.0'
+		classpath 'com.android.tools.build:gradle:4.1.3'
 	}
 }
 
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index 59b5f89..a000141 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -1,5 +1,6 @@
+#Thu Jan 27 15:16:28 PKT 2022
 distributionBase=GRADLE_USER_HOME
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.5-bin.zip
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-5.6.1-bin.zip
-zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
+zipStoreBase=GRADLE_USER_HOME
diff --git a/lib/build.gradle b/lib/build.gradle
index f4893ef..274b7bf 100644
--- a/lib/build.gradle
+++ b/lib/build.gradle
@@ -5,7 +5,7 @@ group = 'com.artifex.mupdf'
 version = '1.19.0'
 
 dependencies {
-	implementation 'androidx.appcompat:appcompat:1.1.+'
+	implementation 'androidx.appcompat:appcompat:1.4.1'
 	if (file('../jni/build.gradle').isFile())
 		api project(':jni')
 	else
@@ -13,10 +13,10 @@ dependencies {
 }
 
 android {
-	compileSdkVersion 28
+	compileSdkVersion 31
 	defaultConfig {
 		minSdkVersion 16
-		targetSdkVersion 28
+		targetSdkVersion 31
 	}
 }
 
diff --git a/lib/src/main/AndroidManifest.xml b/lib/src/main/AndroidManifest.xml
index 2dab3c0..77eeca0 100644
--- a/lib/src/main/AndroidManifest.xml
+++ b/lib/src/main/AndroidManifest.xml
@@ -6,7 +6,7 @@
 		<activity
 			android:name=".DocumentActivity"
 			android:configChanges="orientation|screenSize|keyboardHidden"
-			>
+			android:exported="true">
 			<intent-filter>
 				<!-- match content and file requests with known mime-type -->
 				<action android:name="android.intent.action.VIEW" />