diff --git a/build.gradle b/build.gradle
index 3200257b..510736b9 100644
--- a/build.gradle
+++ b/build.gradle
@@ -1,22 +1,21 @@
-// Top-level build file where you can add configuration options common to all sub-projects/modules.
-
 buildscript {
-    ext.kotlin_version = '1.2.71'
+    ext.kotlin_version = '1.6.0'
+    ext.buildToolsVersion = "30.0.3"
     repositories {
+        mavenCentral()
         jcenter()
         google()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.2.1'
+        classpath 'com.android.tools.build:gradle:7.0.4'
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
-
-        // NOTE: Do not place your application dependencies here; they belong
-        // in the individual module build.gradle files
+        classpath 'com.github.dcendents:android-maven-gradle-plugin:2.0'
     }
 }
 
 allprojects {
     repositories {
+        jcenter()
         mavenLocal()
         jcenter()
         google()
diff --git a/filestack/build.gradle b/filestack/build.gradle
index 09b419d4..b8f45313 100644
--- a/filestack/build.gradle
+++ b/filestack/build.gradle
@@ -1,5 +1,4 @@
 plugins {
-    id 'com.github.dcendents.android-maven' version '2.0'
     id 'com.jfrog.bintray' version '1.7.3'
 }
 
@@ -11,11 +10,11 @@ version = '5.3.0'
 project.archivesBaseName = 'filestack-android'
 
 android {
-    compileSdkVersion 28
+    compileSdkVersion 31
 
     defaultConfig {
-        minSdkVersion 16
-        targetSdkVersion 28
+        minSdkVersion 21
+        targetSdkVersion 31
         versionCode 1
         versionName version
 
@@ -43,7 +42,7 @@ dependencies {
     implementation 'com.android.support:appcompat-v7:28.0.0'
     implementation 'com.android.support:design:28.0.0'
     implementation 'com.android.support:customtabs:28.0.0'
-    
+
     implementation 'com.squareup.picasso:picasso:2.5.2'
     implementation 'io.reactivex.rxjava2:rxandroid:2.1.0'
 
@@ -112,4 +111,4 @@ bintray {
             released = new Date()
         }
     }
-}
+}
\ No newline at end of file
diff --git a/filestack/src/main/AndroidManifest.xml b/filestack/src/main/AndroidManifest.xml
index 1bb5843f..fca6b789 100644
--- a/filestack/src/main/AndroidManifest.xml
+++ b/filestack/src/main/AndroidManifest.xml
@@ -13,6 +13,7 @@
         <activity
             android:name=".FsActivity"
             android:launchMode="singleTop"
+            android:exported="true"
             android:label="@string/filestack__picker_title"
             android:theme="@style/FilestackNoActionBar">
 
diff --git a/filestack/src/main/java/com/filestack/android/FsActivity.java b/filestack/src/main/java/com/filestack/android/FsActivity.java
index 206adf66..4399df7f 100644
--- a/filestack/src/main/java/com/filestack/android/FsActivity.java
+++ b/filestack/src/main/java/com/filestack/android/FsActivity.java
@@ -208,8 +208,11 @@ protected void onStop() {
         super.onStop();
         SharedPreferences preferences = getPreferences(MODE_PRIVATE);
 
-        String sessionToken = Util.getClient().getSessionToken();
-        preferences.edit().putString(PREF_SESSION_TOKEN, sessionToken).apply();
+        if (Util.getClient() != null) {
+            String sessionToken = Util.getClient().getSessionToken();
+            preferences.edit().putString(PREF_SESSION_TOKEN, sessionToken).apply();
+        }
+
         Util.getSelectionSaver().setItemChangeListener(null);
     }
 
@@ -266,8 +269,9 @@ public boolean onCreateOptionsMenu(Menu menu) {
         menu.findItem(R.id.action_about).setVisible(showVersionInfo);
         for (int i = 0; i < menu.size(); i++) {
             MenuItem item = menu.getItem(i);
-            Drawable drawable = DrawableCompat.wrap(item.getIcon());
-            if (drawable != null) {
+            Drawable icon = item.getIcon();
+            Drawable drawable = DrawableCompat.wrap(icon);
+            if (icon != null && drawable != null) {
                 drawable.setColorFilter(theme.getBackgroundColor(), PorterDuff.Mode.SRC_ATOP);
                 DrawableCompat.setTint(drawable, theme.getBackgroundColor());
                 item.setIcon(drawable);
diff --git a/filestack/src/main/java/com/filestack/android/internal/CloudListAdapter.java b/filestack/src/main/java/com/filestack/android/internal/CloudListAdapter.java
index b75481c0..a79b03e6 100644
--- a/filestack/src/main/java/com/filestack/android/internal/CloudListAdapter.java
+++ b/filestack/src/main/java/com/filestack/android/internal/CloudListAdapter.java
@@ -76,6 +76,9 @@ class CloudListAdapter extends RecyclerView.Adapter<CloudListViewHolder> impleme
             currentPath = saveInstanceState.getString(STATE_CURRENT_PATH);
             folders = (HashMap) saveInstanceState.getSerializable(STATE_FOLDERS);
             nextTokens = (HashMap) saveInstanceState.getSerializable(STATE_NEXT_TOKENS);
+            if (folders == null || folders.get(currentPath) == null) {
+                folders.put(currentPath, new ArrayList<CloudItem>());
+            }
         } else {
             folders = new HashMap<>();
             nextTokens = new HashMap<>();
diff --git a/filestack/src/main/java/com/filestack/android/internal/UploadService.java b/filestack/src/main/java/com/filestack/android/internal/UploadService.java
index 27c70197..513262b1 100644
--- a/filestack/src/main/java/com/filestack/android/internal/UploadService.java
+++ b/filestack/src/main/java/com/filestack/android/internal/UploadService.java
@@ -127,7 +127,7 @@ private FileLink upload(Selection selection, StorageOptions baseOptions) {
         String mimeType = selection.getMimeType();
 
         StorageOptions options = baseOptions.newBuilder()
-                .filename(name)
+                .filename(baseOptions.getFilename() + name)
                 .mimeType(mimeType)
                 .build();
 
diff --git a/filestack/src/main/java/com/filestack/android/internal/Util.java b/filestack/src/main/java/com/filestack/android/internal/Util.java
index 2486e168..9f7bfa7a 100644
--- a/filestack/src/main/java/com/filestack/android/internal/Util.java
+++ b/filestack/src/main/java/com/filestack/android/internal/Util.java
@@ -3,6 +3,7 @@
 import android.content.Context;
 import android.content.Intent;
 import android.net.Uri;
+import android.os.Build;
 import android.os.Environment;
 import android.support.v4.content.FileProvider;
 import android.support.v4.content.MimeTypeFilter;
@@ -188,8 +189,14 @@ public static File createMovieFile(Context context) throws IOException {
     // If we don't do this, we'll get the exception when sending the URI to the camera app
     // See the FileProvider example in https://developer.android.com/training/camera/photobasics
     public static Uri getUriForInternalMedia(Context context, File file) {
-        String authority = context.getPackageName() + ".fileprovider";
-        return FileProvider.getUriForFile(context, authority, file);
+        Uri uri;
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
+            String authority = context.getPackageName() + ".fileprovider";
+            uri =  FileProvider.getUriForFile(context, authority, file);
+        } else {
+            uri = Uri.fromFile(file);
+        }
+        return uri;
     }
 
     // TODO This doesn't seem to work
diff --git a/filestack/src/main/res/layout-sw600dp/filestack__activity_filestack.xml b/filestack/src/main/res/layout-sw600dp/filestack__activity_filestack.xml
deleted file mode 100644
index 28a16a6b..00000000
--- a/filestack/src/main/res/layout-sw600dp/filestack__activity_filestack.xml
+++ /dev/null
@@ -1,59 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
-    xmlns:app="http://schemas.android.com/apk/res-auto"
-    xmlns:tools="http://schemas.android.com/tools"
-    android:layout_width="match_parent"
-    android:layout_height="match_parent"
-    tools:context="com.filestack.android.FsActivity">
-
-    <android.support.design.widget.AppBarLayout
-        android:id="@+id/app_bar"
-        android:layout_width="match_parent"
-        android:layout_height="wrap_content"
-        android:theme="@style/FilestackAppBarOverlay">
-
-        <android.support.v7.widget.Toolbar
-            android:id="@+id/toolbar"
-            android:layout_width="match_parent"
-            android:layout_height="?attr/actionBarSize"
-            android:background="?attr/colorPrimary"
-            app:popupTheme="@style/FilestackPopupOverlay" />
-
-    </android.support.design.widget.AppBarLayout>
-
-    <LinearLayout
-        android:layout_marginTop="?attr/actionBarSize"
-        android:orientation="horizontal"
-        android:layout_width="match_parent"
-        android:layout_height="match_parent">
-
-        <android.support.design.widget.NavigationView
-            android:id="@+id/nav_view"
-            android:layout_width="wrap_content"
-            android:layout_height="match_parent"
-            android:fitsSystemWindows="false"
-            app:elevation="0dp"/>
-
-        <View
-            android:id="@+id/divider"
-            android:layout_width="1dp"
-            android:layout_height="match_parent"
-            android:layout_toEndOf="@id/nav_view"
-            android:background="#1E000000"
-            android:layout_toRightOf="@id/nav_view" />
-
-        <FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
-            xmlns:app="http://schemas.android.com/apk/res-auto"
-            xmlns:tools="http://schemas.android.com/tools"
-            android:id="@+id/content"
-            android:layout_width="match_parent"
-            android:layout_height="match_parent"
-            android:layout_toEndOf="@id/divider"
-            app:layout_behavior="@string/appbar_scrolling_view_behavior"
-            tools:context="com.filestack.android.FsActivity"
-            tools:showIn="@layout/filestack__app_bar_filestack"
-            android:layout_toRightOf="@id/divider" />
-
-    </LinearLayout>
-
-</FrameLayout>
diff --git a/gradle.properties b/gradle.properties
index aac7c9b4..82695ffd 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -10,6 +10,7 @@
 # Specifies the JVM arguments used for the daemon process.
 # The setting is particularly useful for tweaking memory settings.
 org.gradle.jvmargs=-Xmx1536m
+android.debug.obsoleteApi=true
 
 # When configured, Gradle will run in incubating parallel mode.
 # This option should only be used with decoupled projects. More details, visit
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index e362f97d..a72b2e8a 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-4.10.2-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.0.2-all.zip
diff --git a/samples/form/app/build.gradle b/samples/form/app/build.gradle
index 5ea2d585..e279ae3c 100644
--- a/samples/form/app/build.gradle
+++ b/samples/form/app/build.gradle
@@ -4,8 +4,8 @@ android {
     compileSdkVersion 27
     defaultConfig {
         applicationId "com.filestack.android.samples.form"
-        minSdkVersion 19
-        targetSdkVersion 27
+        minSdkVersion 21
+        targetSdkVersion 31
         versionCode 1
         versionName "1.0"
         testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
diff --git a/tester/build.gradle b/tester/build.gradle
index 51c44fd4..75307ef3 100644
--- a/tester/build.gradle
+++ b/tester/build.gradle
@@ -5,8 +5,8 @@ android {
 
     defaultConfig {
         applicationId "com.filestack.android.demo"
-        minSdkVersion 16
-        targetSdkVersion 28
+        minSdkVersion 21
+        targetSdkVersion 31
         versionCode 1
         versionName "1.0"
 
diff --git a/tester/src/main/AndroidManifest.xml b/tester/src/main/AndroidManifest.xml
index ce41a559..812477ab 100644
--- a/tester/src/main/AndroidManifest.xml
+++ b/tester/src/main/AndroidManifest.xml
@@ -10,7 +10,8 @@
         android:theme="@style/AppTheme">
 
         <activity
-            android:name=".MainActivity">
+            android:name=".MainActivity"
+            android:exported="true">
 
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />