diff --git a/app/build.gradle b/app/build.gradle
index 024db50..45697a7 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -1,12 +1,12 @@
 apply plugin: 'com.android.application'
 
 android {
-    compileSdkVersion 24
-    buildToolsVersion "24.0.2"
+    compileSdkVersion 25
+    buildToolsVersion "25.0.2"
     defaultConfig {
         applicationId "cafe.adriel.androidaudiorecorder.example"
         minSdkVersion 15
-        targetSdkVersion 24
+        targetSdkVersion 25
         versionCode 1
         versionName "1.0"
     }
@@ -19,8 +19,11 @@ android {
 }
 
 dependencies {
-    compile 'com.android.support:appcompat-v7:24.2.1'
+    compile 'com.android.support:appcompat-v7:25.3.0'
     compile project(':lib')
+    compile ('com.karumi:dexter:2.3.1'){
+        exclude group: 'com.android.support'
+    }
 //    compile 'com.github.adrielcafe:AndroidAudioRecorder:0.1.0'
 }
 
diff --git a/app/src/main/java/cafe/adriel/androidaudiorecorder/example/MainActivity.java b/app/src/main/java/cafe/adriel/androidaudiorecorder/example/MainActivity.java
index 177baa1..6d988b0 100644
--- a/app/src/main/java/cafe/adriel/androidaudiorecorder/example/MainActivity.java
+++ b/app/src/main/java/cafe/adriel/androidaudiorecorder/example/MainActivity.java
@@ -10,6 +10,14 @@
 import android.view.View;
 import android.widget.Toast;
 
+import com.karumi.dexter.Dexter;
+import com.karumi.dexter.MultiplePermissionsReport;
+import com.karumi.dexter.PermissionToken;
+import com.karumi.dexter.listener.PermissionRequest;
+import com.karumi.dexter.listener.multi.MultiplePermissionsListener;
+
+import java.util.List;
+
 import cafe.adriel.androidaudiorecorder.AndroidAudioRecorder;
 import cafe.adriel.androidaudiorecorder.model.AudioChannel;
 import cafe.adriel.androidaudiorecorder.model.AudioSampleRate;
@@ -19,19 +27,33 @@ public class MainActivity extends AppCompatActivity {
     private static final int REQUEST_RECORD_AUDIO = 0;
     private static final String AUDIO_FILE_PATH =
             Environment.getExternalStorageDirectory().getPath() + "/recorded_audio.wav";
+    private boolean hasPermission = false;
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
 
+        Dexter.initialize(this.getApplicationContext());
+
         if (getSupportActionBar() != null) {
             getSupportActionBar().setBackgroundDrawable(
                     new ColorDrawable(ContextCompat.getColor(this, R.color.colorPrimaryDark)));
         }
 
-        Util.requestPermission(this, Manifest.permission.RECORD_AUDIO);
-        Util.requestPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE);
+        Dexter.checkPermissions(new MultiplePermissionsListener() {
+            @Override
+            public void onPermissionsChecked(MultiplePermissionsReport report) {
+                if (report.areAllPermissionsGranted()){
+                    hasPermission = true;
+                }
+            }
+
+            @Override
+            public void onPermissionRationaleShouldBeShown(List<PermissionRequest> permissions, PermissionToken token) {
+                token.continuePermissionRequest();
+            }
+        }, Manifest.permission.RECORD_AUDIO, Manifest.permission.WRITE_EXTERNAL_STORAGE);
     }
 
     @Override
@@ -47,6 +69,10 @@ protected void onActivityResult(int requestCode, int resultCode, Intent data) {
     }
 
     public void recordAudio(View v) {
+        if (! hasPermission){
+            Toast.makeText(this, "no permission", Toast.LENGTH_SHORT).show();
+            return;
+        }
         AndroidAudioRecorder.with(this)
                 // Required
                 .setFilePath(AUDIO_FILE_PATH)
diff --git a/app/src/main/java/cafe/adriel/androidaudiorecorder/example/Util.java b/app/src/main/java/cafe/adriel/androidaudiorecorder/example/Util.java
deleted file mode 100644
index a2b0c82..0000000
--- a/app/src/main/java/cafe/adriel/androidaudiorecorder/example/Util.java
+++ /dev/null
@@ -1,17 +0,0 @@
-package cafe.adriel.androidaudiorecorder.example;
-
-import android.app.Activity;
-import android.content.pm.PackageManager;
-import android.support.v4.app.ActivityCompat;
-import android.support.v4.content.ContextCompat;
-
-public class Util {
-
-    public static void requestPermission(Activity activity, String permission) {
-        if (ContextCompat.checkSelfPermission(activity, permission)
-                != PackageManager.PERMISSION_GRANTED) {
-            ActivityCompat.requestPermissions(activity, new String[]{permission}, 0);
-        }
-    }
-
-}
\ No newline at end of file
diff --git a/build.gradle b/build.gradle
index ccb76fa..ad64a7a 100644
--- a/build.gradle
+++ b/build.gradle
@@ -3,7 +3,7 @@ buildscript {
         jcenter()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:2.2.0'
+        classpath 'com.android.tools.build:gradle:2.3.0'
     }
 }
 
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index 2fac210..21c9f92 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/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-2.14.1-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-3.3-all.zip
diff --git a/lib/build.gradle b/lib/build.gradle
index 2a9c22c..88472d2 100644
--- a/lib/build.gradle
+++ b/lib/build.gradle
@@ -1,12 +1,12 @@
 apply plugin: 'com.android.library'
 
 android {
-    compileSdkVersion 24
-    buildToolsVersion "24.0.2"
+    compileSdkVersion 25
+    buildToolsVersion "25.0.2"
 
     defaultConfig {
         minSdkVersion 15
-        targetSdkVersion 24
+        targetSdkVersion 25
         versionCode 1
         versionName "1.0"
     }
@@ -19,7 +19,7 @@ android {
 }
 
 dependencies {
-    compile 'com.android.support:appcompat-v7:24.2.1'
+    compile 'com.android.support:appcompat-v7:25.3.0'
     compile 'com.kailashdabhi:om-recorder:1.1.0'
     compile 'com.cleveroad:audiovisualization:1.0.0'
 }
\ No newline at end of file