diff --git a/.travis.yml b/.travis.yml
index 0a3c744e..621f4532 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,8 +1,8 @@
 language: php
 php:
-  - 7.1
   - 7.2
   - 7.3
+  - 7.4snapshot
 
 env:
   global:
diff --git a/lib/AppInfo/Application.php b/lib/AppInfo/Application.php
index 51f23027..59b1a9f4 100644
--- a/lib/AppInfo/Application.php
+++ b/lib/AppInfo/Application.php
@@ -25,18 +25,25 @@
 use OCA\Guests\GroupBackend;
 use OCA\Guests\GuestManager;
 use OCA\Guests\Hooks;
+use OCA\Guests\Notifications\Notifier;
 use OCA\Guests\RestrictionManager;
 use OCA\Guests\UserBackend;
 use OCP\AppFramework\App;
+use OCP\IUser;
+use OCP\Notification\IManager as INotificationManager;
 
 class Application extends App {
+
+	public const APP_ID = 'guests';
+
 	public function __construct(array $urlParams = array()) {
-		parent::__construct('guests', $urlParams);
+		parent::__construct(self::APP_ID, $urlParams);
 	}
 
 	public function setup() {
 		$this->setupGuestManagement();
 		$this->setupGuestRestrictions();
+		$this->setupNotifications();
 	}
 
 	public function lateSetup() {
@@ -71,6 +78,10 @@ private function getHookManager() {
 		return $this->getContainer()->query(Hooks::class);
 	}
 
+	private function getNotificationManager(): INotificationManager {
+		return $this->getContainer()->query(INotificationManager::class);
+	}
+
 	private function setupGuestManagement() {
 		$container = $this->getContainer();
 		/** @var Server $server */
@@ -85,7 +96,8 @@ private function setupGuestManagement() {
 			$server->getEventDispatcher()->addListener(
 				'OCA\Files::loadAdditionalScripts',
 				function () {
-					\OCP\Util::addScript('guests', 'main');
+					\OCP\Util::addScript(self::APP_ID, 'main');
+					\OCP\Util::addStyle(self::APP_ID, 'app');
 				}
 			);
 		}
@@ -93,6 +105,7 @@ function () {
 		$server->getGroupManager()->addBackend($container->query(GroupBackend::class));
 		/** @var Hooks $hooks */
 		$server->getEventDispatcher()->addListener('OCP\Share::postShare', [$this->getHookManager(), 'handlePostShare']);
+		$server->getEventDispatcher()->addListener(IUser::class . '::firstLogin', [$this->getHookManager(), 'handleFirstLogin']);
 	}
 
 	private function setupGuestRestrictions() {
@@ -116,4 +129,10 @@ private function setupGuestRestrictions() {
 			});
 		}
 	}
+
+	private function setupNotifications(): void {
+		$notificationManager = $this->getNotificationManager();
+		$notificationManager->registerNotifierService(Notifier::class);
+	}
+
 }
diff --git a/lib/Hooks.php b/lib/Hooks.php
index 8799702e..10aa2801 100644
--- a/lib/Hooks.php
+++ b/lib/Hooks.php
@@ -23,56 +23,62 @@
 namespace OCA\Guests;
 
 use OC\Files\Filesystem;
+use OCA\Files\Exception\TransferOwnershipException;
+use OCA\Files\Service\OwnershipTransferService;
+use OCA\Guests\AppInfo\Application;
 use OCA\Guests\Storage\ReadOnlyJail;
 use OCP\AppFramework\Db\DoesNotExistException;
+use OCP\AppFramework\IAppContainer;
+use OCP\AppFramework\QueryException;
 use OCP\Constants;
-use OCP\Files\IHomeStorage;
 use OCP\Files\Storage\IStorage;
 use OCP\IConfig;
-use OCP\IGroupManager;
 use OCP\ILogger;
 use OCP\IRequest;
+use OCP\IUser;
 use OCP\IUserManager;
 use OCP\IUserSession;
+use OCP\Notification\IManager as INotificationManager;
 use OCP\Security\ICrypto;
+use OCP\Share\IManager as IShareManager;
 use OCP\Share\IShare;
 use Symfony\Component\EventDispatcher\GenericEvent;
 
 
 class Hooks {
 
-	/**
-	 * @var ILogger
-	 */
+	/** @var ILogger */
 	private $logger;
 
-	/**
-	 * @var IUserSession
-	 */
+	/** @var IUserSession */
 	private $userSession;
-	/**
-	 * @var IRequest
-	 */
+
+	/** @var IRequest */
 	private $request;
 
-	/**
-	 * @var Mail
-	 */
+	/** @var Mail */
 	private $mail;
 
-	/**
-	 * @var IUserManager
-	 */
+	/** @var IUserManager */
 	private $userManager;
 
-	/**
-	 * @var ICrypto
-	 */
+	/** @var ICrypto */
 	private $crypto;
 
 	/** @var GuestManager */
 	private $guestManager;
 
+	/** @var UserBackend */
+	private $userBackend;
+
+	/** @var IAppContainer */
+	private $container;
+
+	/** @var INotificationManager */
+	private $notificationManager;
+	/** @var IShareManager */
+	private $shareManager;
+
 	public function __construct(
 		ILogger $logger,
 		IUserSession $userSession,
@@ -81,7 +87,11 @@ public function __construct(
 		IUserManager $userManager,
 		IConfig $config,
 		ICrypto $crypto,
-		GuestManager $guestManager
+		GuestManager $guestManager,
+		UserBackend $userBackend,
+		IAppContainer $container,
+		INotificationManager $notificationManager,
+		IShareManager $shareManager
 	) {
 		$this->logger = $logger;
 		$this->userSession = $userSession;
@@ -91,6 +101,10 @@ public function __construct(
 		$this->config = $config;
 		$this->crypto = $crypto;
 		$this->guestManager = $guestManager;
+		$this->userBackend = $userBackend;
+		$this->container = $container;
+		$this->notificationManager = $notificationManager;
+		$this->shareManager = $shareManager;
 	}
 
 	public function handlePostShare(GenericEvent $event) {
@@ -103,7 +117,7 @@ public function handlePostShare(GenericEvent $event) {
 		if (!$isGuest) {
 			$this->logger->debug(
 				"ignoring user '$shareWith', not a guest",
-				['app' => 'guests']
+				['app' => Application::APP_ID]
 			);
 
 			return;
@@ -112,7 +126,7 @@ public function handlePostShare(GenericEvent $event) {
 		if (!($share->getNodeType() === 'folder' || $share->getNodeType() === 'file')) {
 			$this->logger->debug(
 				"ignoring share for itemType " . $share->getNodeType(),
-				['app' => 'guests']
+				['app' => Application::APP_ID]
 			);
 
 			return;
@@ -129,7 +143,7 @@ public function handlePostShare(GenericEvent $event) {
 		}
 
 		$this->logger->debug("checking if '$shareWith' has a password",
-			['app' => 'guests']);
+			['app' => Application::APP_ID]);
 
 
 		$passwordToken = $this->config->getUserValue(
@@ -160,7 +174,7 @@ public function handlePostShare(GenericEvent $event) {
 				$share->setMailSend(false);
 			}
 		} catch (DoesNotExistException $ex) {
-			$this->logger->error("'$shareWith' does not exist", ['app' => 'guests']);
+			$this->logger->error("'$shareWith' does not exist", ['app' => Application::APP_ID]);
 		}
 	}
 
@@ -182,4 +196,80 @@ public function setupReadonlyFilesystem(array $params) {
 			});
 		}
 	}
+
+	public function handleFirstLogin(GenericEvent $event): void {
+		if ($this->config->getSystemValue('migrate_guest_user_data', false) === false) {
+			return;
+		}
+
+		/** @var IUser $user */
+		$user = $event->getSubject();
+		$this->logger->debug('User ' . $user->getUID() . ' logged in for the very first time. Checking guests data import.');
+
+		$email = $user->getEMailAddress();
+		if ($email === null) {
+			$this->logger->info('User ' . $user->getUID() . ' does not have an e-mail address set. Skipping guests data import.');
+			return;
+		}
+
+		if (!$this->userBackend->userExists($email)) {
+			$this->logger->info('No guest user for ' . $email . ' found. Skipping guests data import.');
+			return;
+		}
+
+		if ($email === $user->getUID()) {
+			// This is the guest user, logging in for the very first time
+			return;
+		}
+
+		try {
+			/** @var OwnershipTransferService $ownershipTransferService */
+			$ownershipTransferService = $this->container->query(OwnershipTransferService::class);
+		} catch (QueryException $e) {
+			$this->logger->logException($e, [
+				'level' => ILogger::ERROR,
+				'message' => 'Could not resolve ownership transfer service to import guest user data',
+			]);
+			return;
+		}
+
+		$guestUser = $this->userManager->get($email);
+		if ($guestUser === null) {
+			$this->logger->warning("Guest user $email does not exist (anymore)");
+			return;
+		}
+		try {
+			$ownershipTransferService->transfer(
+				$guestUser,
+				$user,
+				'/'
+			);
+		} catch (TransferOwnershipException $e) {
+			$this->logger->logException($e, [
+				'level' => ILogger::ERROR,
+				'message' => 'Could not import guest user data',
+			]);
+			return;
+		}
+
+		// Update incomming shares
+		$shares = $this->shareManager->getSharedWith($guestUser->getUID(), IShare::TYPE_USER);
+		foreach ($shares as $share) {
+			$share->setSharedWith($user->getUID());
+			$this->shareManager->updateShare($share);
+		}
+
+		// Disable previous account
+		$guestUser->setEnabled(false);
+
+		$notification = $this->notificationManager->createNotification();
+		$notification
+			->setApp(Application::APP_ID)
+			->setSubject('data_migrated_to_system_user')
+			->setObject('user', $email)
+			->setDateTime(new \DateTime())
+			->setUser($user->getUID());
+		$this->notificationManager->notify($notification);
+	}
+
 }
diff --git a/lib/Notifications/Notifier.php b/lib/Notifications/Notifier.php
new file mode 100644
index 00000000..816c6bea
--- /dev/null
+++ b/lib/Notifications/Notifier.php
@@ -0,0 +1,80 @@
+<?php declare(strict_types=1);
+
+/**
+ * @copyright 2019 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @author 2019 Christoph Wurst <christoph@winzerhof-wurst.at>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+namespace OCA\Guests\Notifications;
+
+use InvalidArgumentException;
+use OCA\Guests\AppInfo\Application;
+use OCP\IURLGenerator;
+use OCP\L10N\IFactory;
+use OCP\Notification\INotification;
+use OCP\Notification\INotifier;
+
+class Notifier implements INotifier {
+
+	/** @var IFactory */
+	private $factory;
+
+	/** @var IURLGenerator */
+	private $url;
+
+	public function __construct(IFactory $factory,
+								IURLGenerator $url) {
+		$this->factory = $factory;
+		$this->url = $url;
+	}
+
+	public function getID(): string {
+		return Application::APP_ID;
+	}
+
+	public function getName(): string {
+		return $this->factory->get(Application::APP_ID)->t('Guests');
+	}
+
+	public function prepare(INotification $notification, string $languageCode): INotification {
+		if ($notification->getApp() !== Application::APP_ID) {
+			// Not my app => throw
+			throw new InvalidArgumentException();
+		}
+
+		// Read the language from the notification
+		$l = $this->factory->get(Application::APP_ID, $languageCode);
+		switch ($notification->getSubject()) {
+			case 'data_migrated_to_system_user':
+				$notification->setParsedSubject(
+					$l->t('Data imported')
+				)->setParsedMessage(
+					$l->t('Data from your previous guest account was successfully imported into your new account.')
+				);
+
+				$notification->setIcon($this->url->getAbsoluteURL($this->url->imagePath('core', 'actions/info.svg')));
+
+				return $notification;
+
+			default:
+				// Unknown subject => Unknown notification => throw
+				throw new InvalidArgumentException();
+		}
+	}
+}
diff --git a/tests/unit/AppWhitelistTest.php b/tests/unit/AppWhitelistTest.php
index 976f6589..8d866711 100644
--- a/tests/unit/AppWhitelistTest.php
+++ b/tests/unit/AppWhitelistTest.php
@@ -28,24 +28,25 @@
 use OCP\IL10N;
 use OCP\IURLGenerator;
 use OCP\IUser;
+use PHPUnit\Framework\MockObject\MockObject;
 use Test\TestCase;
 
 class AppWhitelistTest extends TestCase {
-	/** @var Config|\PHPUnit_Framework_MockObject_MockObject */
+	/** @var Config|MockObject */
 	private $config;
-	/** @var GuestManager|\PHPUnit_Framework_MockObject_MockObject */
+	/** @var GuestManager|MockObject */
 	private $guestManager;
-	/** @var IL10N|\PHPUnit_Framework_MockObject_MockObject */
+	/** @var IL10N|MockObject */
 	private $l10n;
-	/** @var IAppManager|\PHPUnit_Framework_MockObject_MockObject */
+	/** @var IAppManager|MockObject */
 	private $appManager;
-	/** @var IURLGenerator|\PHPUnit_Framework_MockObject_MockObject */
+	/** @var IURLGenerator|MockObject */
 	private $urlGenerator;
 
 	/** @var AppWhitelist */
 	private $appWhitelist;
 
-	protected function setUp() {
+	protected function setUp(): void {
 		parent::setUp();
 
 		$this->config = $this->createMock(Config::class);
diff --git a/tests/unit/GroupBackendTest.php b/tests/unit/GroupBackendTest.php
index 905a77e5..5802ae59 100644
--- a/tests/unit/GroupBackendTest.php
+++ b/tests/unit/GroupBackendTest.php
@@ -26,20 +26,21 @@
 use OCA\Guests\GuestManager;
 use OCP\IUser;
 use OCP\IUserSession;
+use PHPUnit\Framework\MockObject\MockObject;
 use Test\TestCase;
 
 class GroupBackendTest extends TestCase {
-	/** @var GuestManager|\PHPUnit_Framework_MockObject_MockObject */
+	/** @var GuestManager|MockObject */
 	private $guestManager;
-	/** @var Config|\PHPUnit_Framework_MockObject_MockObject */
+	/** @var Config|MockObject */
 	private $config;
-	/** @var IUserSession|\PHPUnit_Framework_MockObject_MockObject */
+	/** @var IUserSession|MockObject */
 	private $userSession;
 
 	/** @var GroupBackend */
 	private $backend;
 
-	protected function setUp() {
+	protected function setUp(): void {
 		parent::setUp();
 
 		$this->guestManager = $this->createMock(GuestManager::class);
diff --git a/tests/unit/GuestManagerTest.php b/tests/unit/GuestManagerTest.php
index 072f2292..1553ba6d 100644
--- a/tests/unit/GuestManagerTest.php
+++ b/tests/unit/GuestManagerTest.php
@@ -31,30 +31,31 @@
 use OCP\Security\ICrypto;
 use OCP\Security\ISecureRandom;
 use OCP\Share\IManager;
+use PHPUnit\Framework\MockObject\MockObject;
 use Test\TestCase;
 
 class GuestManagerTest extends TestCase {
-	/** @var UserBackend|\PHPUnit_Framework_MockObject_MockObject */
+	/** @var UserBackend|MockObject */
 	private $userBackend;
-	/** @var IUserSession|\PHPUnit_Framework_MockObject_MockObject */
+	/** @var IUserSession|MockObject */
 	private $userSession;
-	/** @var IConfig|\PHPUnit_Framework_MockObject_MockObject */
+	/** @var IConfig|MockObject */
 	private $config;
-	/** @var ISecureRandom|\PHPUnit_Framework_MockObject_MockObject */
+	/** @var ISecureRandom|MockObject */
 	private $random;
-	/** @var ICrypto|\PHPUnit_Framework_MockObject_MockObject */
+	/** @var ICrypto|MockObject */
 	private $crypto;
-	/** @var IManager|\PHPUnit_Framework_MockObject_MockObject */
+	/** @var IManager|MockObject */
 	private $shareManager;
-	/** @var IDBConnection|\PHPUnit_Framework_MockObject_MockObject */
+	/** @var IDBConnection|MockObject */
 	private $conneciton;
-	/** @var IEventDispatcher|\PHPUnit_Framework_MockObject_MockObject */
+	/** @var IEventDispatcher|MockObject */
 	private $eventDispatcher;
 
 	/** @var GuestManager */
 	private $guestManager;
 
-	protected function setUp() {
+	protected function setUp(): void {
 		parent::setUp();
 
 		$this->userBackend = $this->createMock(UserBackend::class);
diff --git a/tests/unit/UserBackendTest.php b/tests/unit/UserBackendTest.php
index 603a657f..99e234a6 100644
--- a/tests/unit/UserBackendTest.php
+++ b/tests/unit/UserBackendTest.php
@@ -44,7 +44,7 @@ private function clearGuests() {
 		$query->delete('guests_users')->execute();
 	}
 
-	protected function setUp() {
+	protected function setUp(): void {
 		parent::setUp();
 
 		$this->clearGuests();
@@ -59,10 +59,10 @@ protected function setUp() {
 		);
 	}
 
-	protected function tearDown() {
+	protected function tearDown(): void {
 		$this->clearGuests();
 
-		return parent::tearDown();
+		parent::tearDown();
 	}
 
 	public function testCreate() {