diff --git a/SampleApp/build.gradle b/SampleApp/build.gradle
index 01d4c570..fd30195a 100644
--- a/SampleApp/build.gradle
+++ b/SampleApp/build.gradle
@@ -1,14 +1,16 @@
 buildscript {
     repositories {
         jcenter()
+        google()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:2.3.0'
+        classpath 'com.android.tools.build:gradle:3.0.1'
     }
 }
 
 repositories {
     jcenter()
+    google()
     maven {
         url "https://jitpack.io"
     }
@@ -17,13 +19,12 @@ repositories {
 apply plugin: 'com.android.application'
 
 android {
-    compileSdkVersion 25
-    buildToolsVersion "25.0.2"
+    compileSdkVersion 27
 
     defaultConfig {
         applicationId "io.card.development"
         minSdkVersion 18
-        targetSdkVersion 25
+        targetSdkVersion 27
         versionCode 1
         versionName "1.0.0"
         testInstrumentationRunner 'android.support.test.runner.AndroidJUnitRunner'
@@ -37,10 +38,9 @@ android {
     }
 
     android.applicationVariants.all { variant ->
-        variant.outputs.each { output ->
-            def outputFile = output.outputFile
-            if (outputFile != null && outputFile.name.endsWith('.apk')) {
-                output.outputFile = new File(outputFile.parent, "card.io-sample-app-${variant.name}.apk")
+        variant.outputs.all {
+            if (outputFileName.endsWith('.apk')) {
+                outputFileName = "card.io-sample-app-${variant.name}.apk"
             }
         }
     }
@@ -48,13 +48,11 @@ android {
 
 dependencies {
     if (parent != null) {
-        compile project(':card.io')
+        implementation project(':card.io')
     } else {
-        compile 'io.card:android-sdk:REPLACE_VERSION'
+        implementation 'io.card:android-sdk:REPLACE_VERSION'
     }
-
-    debugCompile 'com.squareup.leakcanary:leakcanary-android:1.4'
-
-    androidTestCompile "com.android.support.test.espresso:espresso-core:2.2.2"
-    androidTestCompile "com.github.lkorth:device-automator:01d85912ec"
+    debugImplementation 'com.squareup.leakcanary:leakcanary-android:1.4'
+    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2-alpha1'
+    androidTestImplementation 'com.github.lkorth:device-automator:01d85912ec'
 }
diff --git a/SampleApp/src/main/java/io/card/development/SampleActivity.java b/SampleApp/src/main/java/io/card/development/SampleActivity.java
index ac3a5120..8c8aa7b0 100644
--- a/SampleApp/src/main/java/io/card/development/SampleActivity.java
+++ b/SampleApp/src/main/java/io/card/development/SampleActivity.java
@@ -56,6 +56,8 @@ public class SampleActivity extends Activity {
     private CheckBox mUseCardIOLogoToggle;
     private CheckBox mShowPayPalActionBarIconToggle;
     private CheckBox mKeepApplicationThemeToggle;
+    private CheckBox mLockOrientationToggle;
+    private CheckBox mAddOverlayToggle;
     private Spinner mLanguageSpinner;
     private EditText mUnblurEdit;
 
@@ -64,29 +66,32 @@ public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.sample_activity);
 
-        mManualToggle = (CheckBox) findViewById(R.id.force_manual);
-        mEnableExpiryToggle = (CheckBox) findViewById(R.id.gather_expiry);
-        mScanExpiryToggle = (CheckBox) findViewById(R.id.scan_expiry);
-        mCvvToggle = (CheckBox) findViewById(R.id.gather_cvv);
-        mPostalCodeToggle = (CheckBox) findViewById(R.id.gather_postal_code);
-        mPostalCodeNumericOnlyToggle = (CheckBox) findViewById(R.id.postal_code_numeric_only);
-        mCardholderNameToggle = (CheckBox) findViewById(R.id.gather_cardholder_name);
-        mSuppressManualToggle = (CheckBox) findViewById(R.id.suppress_manual);
-        mSuppressConfirmationToggle = (CheckBox) findViewById(R.id.suppress_confirmation);
-        mSuppressScanToggle = (CheckBox) findViewById(R.id.detect_only);
-
-        mUseCardIOLogoToggle = (CheckBox) findViewById(R.id.use_card_io_logo);
-        mShowPayPalActionBarIconToggle = (CheckBox) findViewById(R.id.show_paypal_action_bar_icon);
-        mKeepApplicationThemeToggle = (CheckBox) findViewById(R.id.keep_application_theme);
-
-        mLanguageSpinner = (Spinner) findViewById(R.id.language);
-        mUnblurEdit = (EditText) findViewById(R.id.unblur);
-
-        mResultLabel = (TextView) findViewById(R.id.result);
-        mResultImage = (ImageView) findViewById(R.id.result_image);
-        mResultCardTypeImage = (ImageView) findViewById(R.id.result_card_type_image);
-
-        TextView version = (TextView) findViewById(R.id.version);
+        mManualToggle = findViewById(R.id.force_manual);
+        mEnableExpiryToggle = findViewById(R.id.gather_expiry);
+        mScanExpiryToggle = findViewById(R.id.scan_expiry);
+        mCvvToggle = findViewById(R.id.gather_cvv);
+        mPostalCodeToggle = findViewById(R.id.gather_postal_code);
+        mPostalCodeNumericOnlyToggle = findViewById(R.id.postal_code_numeric_only);
+        mCardholderNameToggle = findViewById(R.id.gather_cardholder_name);
+        mSuppressManualToggle = findViewById(R.id.suppress_manual);
+        mSuppressConfirmationToggle = findViewById(R.id.suppress_confirmation);
+        mSuppressScanToggle = findViewById(R.id.detect_only);
+
+        mUseCardIOLogoToggle = findViewById(R.id.use_card_io_logo);
+        mShowPayPalActionBarIconToggle = findViewById(R.id.show_paypal_action_bar_icon);
+        mKeepApplicationThemeToggle = findViewById(R.id.keep_application_theme);
+
+        mLockOrientationToggle = findViewById(R.id.lock_orientation);
+        mAddOverlayToggle = findViewById(R.id.add_overlay);
+
+        mLanguageSpinner = findViewById(R.id.language);
+        mUnblurEdit = findViewById(R.id.unblur);
+
+        mResultLabel = findViewById(R.id.result);
+        mResultImage = findViewById(R.id.result_image);
+        mResultCardTypeImage = findViewById(R.id.result_card_type_image);
+
+        TextView version = findViewById(R.id.version);
         version.setText("card.io library: " + CardIOActivity.sdkVersion() + "\n" +
                 "Build date: " + CardIOActivity.sdkBuildDate());
 
@@ -116,11 +121,16 @@ public void onScan(View pressed) {
                 .putExtra(CardIOActivity.EXTRA_LANGUAGE_OR_LOCALE, (String) mLanguageSpinner.getSelectedItem())
                 .putExtra(CardIOActivity.EXTRA_USE_PAYPAL_ACTIONBAR_ICON, mShowPayPalActionBarIconToggle.isChecked())
                 .putExtra(CardIOActivity.EXTRA_KEEP_APPLICATION_THEME, mKeepApplicationThemeToggle.isChecked())
+                .putExtra(CardIOActivity.EXTRA_LOCK_ORIENTATION, mLockOrientationToggle.isChecked())
                 .putExtra(CardIOActivity.EXTRA_GUIDE_COLOR, Color.GREEN)
                 .putExtra(CardIOActivity.EXTRA_SUPPRESS_CONFIRMATION, mSuppressConfirmationToggle.isChecked())
                 .putExtra(CardIOActivity.EXTRA_SUPPRESS_SCAN, mSuppressScanToggle.isChecked())
                 .putExtra(CardIOActivity.EXTRA_RETURN_CARD_IMAGE, true);
 
+        if (mAddOverlayToggle.isChecked()) {
+            intent.putExtra(CardIOActivity.EXTRA_SCAN_OVERLAY_LAYOUT_ID, R.layout.overlay_layout);
+        }
+
         try {
             int unblurDigits = Integer.parseInt(mUnblurEdit.getText().toString());
             intent.putExtra(CardIOActivity.EXTRA_UNBLUR_DIGITS, unblurDigits);
diff --git a/SampleApp/src/main/res/layout/overlay_layout.xml b/SampleApp/src/main/res/layout/overlay_layout.xml
new file mode 100644
index 00000000..1906e5e9
--- /dev/null
+++ b/SampleApp/src/main/res/layout/overlay_layout.xml
@@ -0,0 +1,32 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:orientation="vertical"
+    android:padding="32dp">
+
+    <TextView
+        android:id="@+id/textView"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_weight="1"
+        android:gravity="top|center_horizontal"
+        android:text="OVERLAY MESSAGE" />
+
+    <TextView
+        android:id="@+id/textView2"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_weight="1"
+        android:gravity="center"
+        android:text="OVERLAY MESSAGE" />
+
+    <TextView
+        android:id="@+id/textView3"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_weight="1"
+        android:gravity="bottom|center_horizontal"
+        android:text="OVERLAY MESSAGE" />
+
+</LinearLayout>
diff --git a/SampleApp/src/main/res/layout/sample_activity.xml b/SampleApp/src/main/res/layout/sample_activity.xml
index 5444e783..59b39029 100644
--- a/SampleApp/src/main/res/layout/sample_activity.xml
+++ b/SampleApp/src/main/res/layout/sample_activity.xml
@@ -110,6 +110,18 @@
             android:layout_height="wrap_content"
             android:text="Keep application theme"/>
 
+        <CheckBox
+            android:id="@+id/lock_orientation"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:text="Lock orientation"/>
+
+        <CheckBox
+            android:id="@+id/add_overlay"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:text="Show sample overlay layout"/>
+
         <LinearLayout
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
diff --git a/build.gradle b/build.gradle
index 415f8368..4436660a 100644
--- a/build.gradle
+++ b/build.gradle
@@ -1,9 +1,10 @@
 buildscript {
     repositories {
         jcenter()
+        google()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:2.3.0'
+        classpath 'com.android.tools.build:gradle:3.0.1'
         classpath "io.codearte.gradle.nexus:gradle-nexus-staging-plugin:0.5.3"
     }
 }
@@ -11,6 +12,10 @@ buildscript {
 task assemble {}
 
 ext {
-    sdkVersion = 25
-    buildToolsVersion = '25.0.2'
+    sdkVersion = 27
+    buildToolsVersion = '27.0.3'
+}
+
+repositories {
+    google()
 }
diff --git a/card.io/build.gradle b/card.io/build.gradle
index 1c0d2184..9094b9f2 100644
--- a/card.io/build.gradle
+++ b/card.io/build.gradle
@@ -34,8 +34,8 @@ android {
 }
 
 dependencies {
-    testCompile "junit:junit:4.12"
-    testCompile "org.robolectric:robolectric:3.1.2"
+    testImplementation "junit:junit:4.12"
+    testImplementation "org.robolectric:robolectric:3.1.2"
 }
 
 task javadocs(type: Javadoc) {
@@ -50,6 +50,7 @@ task javadocs(type: Javadoc) {
     options.version(true)
     options.use(true)
     options.setMemberLevel(JavadocMemberLevel.PUBLIC)
+    options.encoding = 'UTF-8'
 
     // enables links to Java 7 docs
     options.links("http://docs.oracle.com/javase/7/docs/api/")
diff --git a/card.io/src/main/java/io/card/payment/CardIOActivity.java b/card.io/src/main/java/io/card/payment/CardIOActivity.java
index 961eb522..d2ab8ec9 100644
--- a/card.io/src/main/java/io/card/payment/CardIOActivity.java
+++ b/card.io/src/main/java/io/card/payment/CardIOActivity.java
@@ -220,6 +220,12 @@ public final class CardIOActivity extends Activity {
      */
     public static final String EXTRA_KEEP_APPLICATION_THEME = "io.card.payment.keepApplicationTheme";
 
+    /**
+     * Boolean extra. Optional. If this value is set to <code>true</code>, the scanner view will
+     * remain in portrait mode.  Default value is {@code false}.
+     */
+    public static final String EXTRA_LOCK_ORIENTATION = "io.card.payment.lockOrientation";
+
 
     /**
      * Boolean extra. Used for testing only.
@@ -305,6 +311,8 @@ public final class CardIOActivity extends Activity {
 
     private boolean manualEntryFallbackOrForced = false;
 
+    private boolean mOrientationLocked;
+
     /**
      * Static variable for the decorated card image. This is ugly, but works. Parceling and
      * unparceling card image data to pass to the next {@link android.app.Activity} does not work because the image
@@ -326,6 +334,8 @@ protected void onCreate(Bundle savedInstanceState) {
 
         final Intent clientData = this.getIntent();
 
+        mOrientationLocked = clientData.getBooleanExtra(EXTRA_LOCK_ORIENTATION, false);
+
         useApplicationTheme = getIntent().getBooleanExtra(CardIOActivity.EXTRA_KEEP_APPLICATION_THEME, false);
         ActivityHelper.setActivityTheme(this, useApplicationTheme);
 
@@ -468,13 +478,15 @@ private void showCameraScannerOverlay() {
 
             setPreviewLayout();
 
-            orientationListener = new OrientationEventListener(this,
-                    SensorManager.SENSOR_DELAY_UI) {
-                @Override
-                public void onOrientationChanged(int orientation) {
-                    doOrientationChange(orientation);
-                }
-            };
+            if (!mOrientationLocked) {
+                orientationListener = new OrientationEventListener(this,
+                        SensorManager.SENSOR_DELAY_UI) {
+                    @Override
+                    public void onOrientationChanged(int orientation) {
+                        doOrientationChange(orientation);
+                    }
+                };
+            }
 
         } catch (Exception e) {
             handleGeneralExceptionError(e);
@@ -497,7 +509,7 @@ private void doOrientationChange(int orientation) {
             return;
         }
 
-        orientation += mCardScanner.getRotationalOffset();
+        orientation += mOrientationLocked ? 0 : mCardScanner.getRotationalOffset();
 
         // Check if we have gone too far forward with
         // rotation adjustment, keep the result between 0-360
@@ -560,7 +572,10 @@ protected void onResume() {
             ActivityHelper.setFlagSecure(this);
 
             setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
-            orientationListener.enable();
+
+            if (orientationListener != null && !mOrientationLocked) {
+                orientationListener.enable();
+            }
 
             if (!restartPreview()) {
                 StringKey error = StringKey.ERROR_CAMERA_UNEXPECTED_FAIL;
@@ -571,7 +586,7 @@ protected void onResume() {
                 setFlashOn(false);
             }
 
-            doOrientationChange(mLastDegrees);
+            doOrientationChange(mOrientationLocked ? 0 : mLastDegrees);
         }
     }
 
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index 0a48d7d6..d09d2ec7 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-3.3-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.1-all.zip