diff --git a/CacheCleaner/build.gradle b/CacheCleaner/build.gradle
index 38ba063..d595e79 100644
--- a/CacheCleaner/build.gradle
+++ b/CacheCleaner/build.gradle
@@ -3,9 +3,14 @@ import org.ajoberstar.grgit.Grgit
 buildscript {
     repositories {
         jcenter()
+        maven {
+            url 'https://maven.google.com/'
+            name 'Google'
+        }
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:2.1.2'
+//        classpath 'com.android.tools.build:gradle:2.1.2'
+        classpath 'com.android.tools.build:gradle:3.1.2'
         classpath 'org.ajoberstar:gradle-git:1.4.2'
     }
 }
@@ -13,6 +18,10 @@ apply plugin: 'com.android.application'
 
 repositories {
     mavenCentral()
+    maven {
+        url 'https://maven.google.com/'
+        name 'Google'
+    }
 }
 
 ext {
@@ -22,13 +31,13 @@ ext {
 }
 
 android {
-    compileSdkVersion 23
-    buildToolsVersion "23.0.3"
+    compileSdkVersion 27
+    buildToolsVersion '27.0.3'
 
     defaultConfig {
         applicationId "com.frozendevs.cache.cleaner"
-        minSdkVersion 9
-        targetSdkVersion 23
+        minSdkVersion 15
+        targetSdkVersion 27
         versionCode = gitVersionCode
         versionName = gitVersionName
 
@@ -36,8 +45,8 @@ android {
     }
 
     compileOptions {
-        sourceCompatibility JavaVersion.VERSION_1_7
-        targetCompatibility JavaVersion.VERSION_1_7
+        sourceCompatibility JavaVersion.VERSION_1_8
+        targetCompatibility JavaVersion.VERSION_1_8
     }
 
     buildTypes {
@@ -57,10 +66,10 @@ android {
 }
 
 dependencies {
-    compile('com.android.support:support-v4:23.4.0')
-    compile('com.android.support:appcompat-v7:23.4.0@aar')
-    compile('com.android.support:recyclerview-v7:23.4.0@aar')
-    compile('com.android.support:support-vector-drawable:23.4.0@aar')
+    implementation 'com.android.support:support-v4:27.1.1'
+    implementation 'com.android.support:appcompat-v7:27.1.1'
+    implementation 'com.android.support:recyclerview-v7:27.1.1'
+    implementation 'com.android.support:support-vector-drawable:27.1.1'
 }
 
 if (project.hasProperty("CacheCleaner.signing") &&
diff --git a/CacheCleaner/src/main/AndroidManifest.xml b/CacheCleaner/src/main/AndroidManifest.xml
index d3f142c..9a7e3a8 100644
--- a/CacheCleaner/src/main/AndroidManifest.xml
+++ b/CacheCleaner/src/main/AndroidManifest.xml
@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
     package="com.frozendevs.cache.cleaner"
     android:installLocation="internalOnly">
 
@@ -8,6 +9,10 @@
     <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
     <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
 
+    <uses-permission
+        android:name="android.permission.PACKAGE_USAGE_STATS"
+        tools:ignore="ProtectedPermissions" />
+
     <supports-screens
         android:anyDensity="true"
         android:largeScreens="true"
diff --git a/CacheCleaner/src/main/java/com/frozendevs/cache/cleaner/activity/CleanerActivity.java b/CacheCleaner/src/main/java/com/frozendevs/cache/cleaner/activity/CleanerActivity.java
index 5b4353a..ca5bac8 100644
--- a/CacheCleaner/src/main/java/com/frozendevs/cache/cleaner/activity/CleanerActivity.java
+++ b/CacheCleaner/src/main/java/com/frozendevs/cache/cleaner/activity/CleanerActivity.java
@@ -1,16 +1,56 @@
 package com.frozendevs.cache.cleaner.activity;
 
+import android.app.AppOpsManager;
+import android.app.usage.UsageStats;
+import android.app.usage.UsageStatsManager;
+import android.content.Context;
+import android.os.Build;
 import android.os.Bundle;
 import android.support.v7.app.AppCompatActivity;
 
 import com.frozendevs.cache.cleaner.R;
 
-public class CleanerActivity extends AppCompatActivity {
+import java.util.List;
 
+public class CleanerActivity extends AppCompatActivity {
+    public final static int USAGE_ACCESS_SETTINGS = 1;
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
 
         setContentView(R.layout.cleaner_activity);
     }
+
+
+    public static boolean checkUsageStatsEnabled(Context context) {
+        // Usage Stats is theoretically available on API v19+, but official/reliable support starts with API v21.
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
+            return false;
+        }
+
+        final AppOpsManager appOpsManager = (AppOpsManager) context.getSystemService(Context.APP_OPS_SERVICE);
+
+        if (appOpsManager == null) {
+            return false;
+        }
+
+        final int mode = appOpsManager.checkOpNoThrow(AppOpsManager.OPSTR_GET_USAGE_STATS, android.os.Process.myUid(), context.getPackageName());
+        if (mode != AppOpsManager.MODE_ALLOWED) {
+            return false;
+        }
+
+        // Verify that access is possible. Some devices "lie" and return MODE_ALLOWED even when it's not.
+        final long now = System.currentTimeMillis();
+        final UsageStatsManager mUsageStatsManager;
+        List<UsageStats> stats = null;
+
+        if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.LOLLIPOP_MR1) {
+            mUsageStatsManager = (UsageStatsManager) context.getSystemService(Context.USAGE_STATS_SERVICE);
+            if (mUsageStatsManager != null) {
+                stats = mUsageStatsManager.queryUsageStats(UsageStatsManager.INTERVAL_DAILY, now - 1000 * 10, now);
+            }
+        }
+
+        return (stats != null && !stats.isEmpty());
+    }
 }
diff --git a/CacheCleaner/src/main/java/com/frozendevs/cache/cleaner/fragment/CleanerFragment.java b/CacheCleaner/src/main/java/com/frozendevs/cache/cleaner/fragment/CleanerFragment.java
index cad0a32..28ac7be 100644
--- a/CacheCleaner/src/main/java/com/frozendevs/cache/cleaner/fragment/CleanerFragment.java
+++ b/CacheCleaner/src/main/java/com/frozendevs/cache/cleaner/fragment/CleanerFragment.java
@@ -1,6 +1,8 @@
 package com.frozendevs.cache.cleaner.fragment;
 
 import android.Manifest;
+import android.annotation.TargetApi;
+import android.app.Activity;
 import android.app.ProgressDialog;
 import android.content.ComponentName;
 import android.content.Context;
@@ -15,6 +17,7 @@
 import android.os.IBinder;
 import android.os.StatFs;
 import android.preference.PreferenceManager;
+import android.provider.Settings;
 import android.support.annotation.NonNull;
 import android.support.v4.app.Fragment;
 import android.support.v4.view.MenuItemCompat;
@@ -34,6 +37,7 @@
 import android.widget.Toast;
 
 import com.frozendevs.cache.cleaner.R;
+import com.frozendevs.cache.cleaner.activity.CleanerActivity;
 import com.frozendevs.cache.cleaner.activity.SettingsActivity;
 import com.frozendevs.cache.cleaner.model.AppsListItem;
 import com.frozendevs.cache.cleaner.model.CleanerService;
@@ -43,6 +47,8 @@
 
 import java.util.List;
 
+import static com.frozendevs.cache.cleaner.activity.CleanerActivity.USAGE_ACCESS_SETTINGS;
+
 public class CleanerFragment extends Fragment implements CleanerService.OnActionListener {
 
     private static final int REQUEST_STORAGE = 0;
@@ -96,10 +102,10 @@ public void onServiceDisconnected(ComponentName name) {
         }
     };
 
+
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
-
         setHasOptionsMenu(true);
         setRetainInstance(true);
 
@@ -123,6 +129,59 @@ public boolean onKey(DialogInterface dialog, int keyCode, KeyEvent event) {
             }
         });
 
+        startService();
+    }
+
+
+    void startService() {
+
+        if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
+
+            boolean usageStats = CleanerActivity.checkUsageStatsEnabled(getActivity());
+
+            if (usageStats) {
+
+                startCleanerService();
+
+            } else {
+
+                showDialog(getActivity(), "Usage Access Settings", "You need to allow Usage Access Settings to access cache of all app.");
+            }
+        } else {
+            startCleanerService();
+        }
+    }
+
+    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
+    public void showDialog(Activity activity, String title, CharSequence message) {
+        AlertDialog.Builder builder = new AlertDialog.Builder(activity);
+
+        if (title != null) builder.setTitle(title);
+
+        builder.setMessage(message);
+        builder.setPositiveButton("Allow", new DialogInterface.OnClickListener() {
+
+            @Override
+            public void onClick(DialogInterface dialogInterface, int i) {
+
+                Intent usageIntent = new Intent(Settings.ACTION_USAGE_ACCESS_SETTINGS);
+                startActivityForResult(usageIntent, USAGE_ACCESS_SETTINGS);
+            }
+        });
+        builder.setCancelable(false);
+        builder.show();
+    }
+
+    @Override
+    public void onActivityResult(int requestCode, int resultCode, Intent data) {
+        super.onActivityResult(requestCode, resultCode, data);
+
+        if (requestCode == USAGE_ACCESS_SETTINGS)
+            startService();
+
+    }
+
+    private void startCleanerService() {
         getActivity().getApplication().bindService(new Intent(getActivity(), CleanerService.class),
                 mServiceConnection, Context.BIND_AUTO_CREATE);
     }
diff --git a/CacheCleaner/src/main/java/com/frozendevs/cache/cleaner/model/CleanerService.java b/CacheCleaner/src/main/java/com/frozendevs/cache/cleaner/model/CleanerService.java
index cac10c1..227bac6 100644
--- a/CacheCleaner/src/main/java/com/frozendevs/cache/cleaner/model/CleanerService.java
+++ b/CacheCleaner/src/main/java/com/frozendevs/cache/cleaner/model/CleanerService.java
@@ -2,6 +2,8 @@
 
 import android.Manifest;
 import android.app.Service;
+import android.app.usage.StorageStats;
+import android.app.usage.StorageStatsManager;
 import android.content.Context;
 import android.content.Intent;
 import android.content.pm.ApplicationInfo;
@@ -17,6 +19,7 @@
 import android.os.IBinder;
 import android.os.RemoteException;
 import android.os.StatFs;
+import android.os.storage.StorageManager;
 import android.support.v4.content.ContextCompat;
 import android.util.Log;
 import android.widget.Toast;
@@ -30,6 +33,8 @@
 import java.util.List;
 import java.util.concurrent.CountDownLatch;
 
+import static android.content.pm.PackageManager.GET_META_DATA;
+
 public class CleanerService extends Service {
 
     public static final String ACTION_CLEAN_AND_EXIT = "com.frozendevs.cache.cleaner.CLEAN_AND_EXIT";
@@ -83,36 +88,69 @@ protected List<AppsListItem> doInBackground(Void... params) {
 
             publishProgress(0, packages.size());
 
-            final CountDownLatch countDownLatch = new CountDownLatch(packages.size());
 
             final List<AppsListItem> apps = new ArrayList<>();
 
-            try {
+            if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+
+                final StorageStatsManager storageStatsManager = (StorageStatsManager) getSystemService(Context.STORAGE_STATS_SERVICE);
+
+                final StorageManager storageManager = (StorageManager) getSystemService(Context.STORAGE_SERVICE);
+
                 for (ApplicationInfo pkg : packages) {
-                    mGetPackageSizeInfoMethod.invoke(getPackageManager(), pkg.packageName,
-                            new IPackageStatsObserver.Stub() {
 
-                                @Override
-                                public void onGetStatsCompleted(PackageStats pStats,
-                                                                boolean succeeded)
-                                        throws RemoteException {
-                                    synchronized (apps) {
-                                        publishProgress(++mAppCount, packages.size());
+                    try {
 
-                                        mCacheSize += addPackage(apps, pStats, succeeded);
-                                    }
+                        ApplicationInfo info = getPackageManager().getApplicationInfo(pkg.packageName, GET_META_DATA);
+                        StorageStats storageStats = storageStatsManager.queryStatsForUid(info.storageUuid, info.uid);
+
+                        publishProgress(++mAppCount, packages.size());
+                        long cacheSize = storageStats.getCacheBytes();
+                        mCacheSize += cacheSize;
+
+                        try {
+                            PackageManager packageManager = getPackageManager();
+
+                            apps.add(new AppsListItem(pkg.packageName,
+                                    packageManager.getApplicationLabel(info).toString(),
+                                    packageManager.getApplicationIcon(pkg.packageName),
+                                    cacheSize));
+                        } catch (PackageManager.NameNotFoundException e) {
+                            e.printStackTrace();
+                        }
 
-                                    synchronized (countDownLatch) {
-                                        countDownLatch.countDown();
+                    } catch (Exception ignored) {
+                    }
+                }
+            } else {
+                final CountDownLatch countDownLatch = new CountDownLatch(packages.size());
+                try {
+                    for (ApplicationInfo pkg : packages) {
+                        mGetPackageSizeInfoMethod.invoke(getPackageManager(), pkg.packageName,
+                                new IPackageStatsObserver.Stub() {
+
+                                    @Override
+                                    public void onGetStatsCompleted(PackageStats pStats,
+                                                                    boolean succeeded)
+                                            throws RemoteException {
+                                        synchronized (apps) {
+                                            publishProgress(++mAppCount, packages.size());
+
+                                            mCacheSize += addPackage(apps, pStats, succeeded);
+                                        }
+
+                                        synchronized (countDownLatch) {
+                                            countDownLatch.countDown();
+                                        }
                                     }
                                 }
-                            }
-                    );
-                }
+                        );
+                    }
 
-                countDownLatch.await();
-            } catch (InvocationTargetException | InterruptedException | IllegalAccessException e) {
-                e.printStackTrace();
+                    countDownLatch.await();
+                } catch (InvocationTargetException | InterruptedException | IllegalAccessException e) {
+                    e.printStackTrace();
+                }
             }
 
             return new ArrayList<>(apps);
@@ -339,8 +377,7 @@ public void onCleanStarted(Context context) {
                 public void onCleanCompleted(Context context, boolean succeeded) {
                     if (succeeded) {
                         Log.d(TAG, "Cache cleaned");
-                    }
-                    else {
+                    } else {
                         Log.e(TAG, "Could not clean the cache");
                     }
 
diff --git a/build.gradle b/build.gradle
index 495c503..02ffbad 100644
--- a/build.gradle
+++ b/build.gradle
@@ -1 +1,10 @@
 // Top-level build file where you can add configuration options common to all sub-projects/modules.
+
+buildscript {
+    repositories {
+        maven {
+            url 'https://maven.google.com/'
+            name 'Google'
+        }
+    }
+}