diff --git a/README.md b/README.md
index 0bad94b..cc95816 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,12 @@
 External user authentication
 ============================
+
+**⚠⚠ Warning:** As of Version 3.0 this app uses namespace \OCA\UserExternal now. You MUST change your config to adopt to this change. ⚠⚠
+
+## Usage
+
+Go to Apps-Folder of your Nextcloud Installation
+
 **Authenticate user login against IMAP, SMB, FTP, WebDAV, HTTP BasicAuth, SSH and XMPP**
 
 Passwords are not stored locally; authentication always happens against
@@ -30,7 +37,7 @@ Add the following to `config.php`:
 
     'user_backends' => array(
         array(
-            'class' => 'OC_User_FTP',
+            'class' => '\OCA\UserExternal\FTP',
             'arguments' => array('127.0.0.1'),
         ),
     ),
@@ -39,7 +46,7 @@ To enable SSL connections via `ftps`, append a second parameter `true`:
 
     'user_backends' => array(
         array(
-            'class' => 'OC_User_FTP',
+            'class' => '\OCA\UserExternal\FTP',
             'arguments' => array('127.0.0.1', true),
         ),
     ),
@@ -68,7 +75,7 @@ Add the following to your `config.php`:
 
     'user_backends' => array(
         array(
-            'class' => 'OC_User_IMAP',
+            'class' => '\OCA\UserExternal\IMAP',
             'arguments' => array(
                 '127.0.0.1', 993, 'ssl', 'example.com', true, false
             ),
@@ -104,7 +111,7 @@ Add the following to your `config.php`:
 
     'user_backends' => array(
         array(
-            'class' => 'OC_User_SMB',
+            'class' => '\OCA\UserExternal\SMB',
             'arguments' => array('127.0.0.1'),
         ),
     ),
@@ -128,7 +135,7 @@ Add the following to your `config.php`:
 
     'user_backends' => array(
         array(
-            'class' => '\OCA\User_External\WebDAVAuth',
+            'class' => '\OCA\UserExternal\WebDAVAuth',
             'arguments' => array('https://example.com/webdav'),
         ),
     ),
@@ -151,7 +158,7 @@ Add the following to your `config.php`:
 
     'user_backends' => array(
         array(
-            'class' => 'OC_User_BasicAuth',
+            'class' => '\OCA\UserExternal\BasicAuth',
             'arguments' => array('https://example.com/basic_auth'),
         ),
     ),
@@ -172,7 +179,7 @@ Add the following to your `config.php`:
 
     'user_backends' => array(
         array(
-            'class' => 'OC_User_SSH',
+            'class' => '\OCA\UserExternal\SSH',
             'arguments' => array('127.0.0.1', '22'),
         ),
     ),
@@ -193,7 +200,7 @@ Add the following to your `config.php`:
 
     'user_backends' => array (
         0 => array (
-            'class' => 'OC_User_XMPP',
+            'class' => '\OCA\UserExternal\XMPP',
                 'arguments' => array (
                     0 => 'dbhost',
                     1 => 'prosodydb',
diff --git a/appinfo/app.php b/appinfo/app.php
deleted file mode 100644
index 6c3b095..0000000
--- a/appinfo/app.php
+++ /dev/null
@@ -1,7 +0,0 @@
-<?php
-OC::$CLASSPATH['OC_User_IMAP']='user_external/lib/imap.php';
-OC::$CLASSPATH['OC_User_SMB']='user_external/lib/smb.php';
-OC::$CLASSPATH['OC_User_FTP']='user_external/lib/ftp.php';
-OC::$CLASSPATH['OC_User_BasicAuth']='user_external/lib/basicauth.php';
-OC::$CLASSPATH['OC_User_SSH']='user_external/lib/ssh.php';
-OC::$CLASSPATH['OC_User_XMPP']='user_external/lib/xmpp.php';
diff --git a/appinfo/info.xml b/appinfo/info.xml
index d9c08b6..1c31b42 100644
--- a/appinfo/info.xml
+++ b/appinfo/info.xml
@@ -32,6 +32,6 @@ Read the [documentation](https://github.com/nextcloud/user_external#readme) to l
 	<bugs>https://github.com/nextcloud/user_external/issues</bugs>
 	<repository type="git">https://github.com/nextcloud/user_external.git</repository>
 	<dependencies>
-		<nextcloud min-version="21" max-version="22" />
+		<nextcloud min-version="21" max-version="23" />
 	</dependencies>
 </info>
diff --git a/lib/AppInfo/Application.php b/lib/AppInfo/Application.php
new file mode 100644
index 0000000..05dec26
--- /dev/null
+++ b/lib/AppInfo/Application.php
@@ -0,0 +1,26 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OCA\UserExternal\AppInfo;
+
+use OCP\AppFramework\App;
+use OCP\AppFramework\Bootstrap\IBootContext;
+use OCP\AppFramework\Bootstrap\IBootstrap;
+use OCP\AppFramework\Bootstrap\IRegistrationContext;
+use OCP\Notification\IManager;
+use OCP\User\Events;
+
+class Application extends App implements IBootstrap {
+
+    public function __construct() {
+        parent::__construct('user_external');
+    }
+
+    public function register(IRegistrationContext $context): void {
+    }
+
+    public function boot(IBootContext $context): void {
+    }
+
+}
\ No newline at end of file
diff --git a/lib/base.php b/lib/Base.php
similarity index 99%
rename from lib/base.php
rename to lib/Base.php
index 8813cf4..08b4138 100644
--- a/lib/base.php
+++ b/lib/Base.php
@@ -7,7 +7,7 @@
  * later.
  * See the COPYING-README file.
  */
-namespace OCA\user_external;
+namespace OCA\UserExternal;
 
 /**
  * Base class for external auth implementations that stores users
diff --git a/lib/basicauth.php b/lib/BasicAuth.php
similarity index 91%
rename from lib/basicauth.php
rename to lib/BasicAuth.php
index 5963972..7d6222f 100644
--- a/lib/basicauth.php
+++ b/lib/BasicAuth.php
@@ -6,7 +6,9 @@
  * See the COPYING-README file.
  */
 
-class OC_User_BasicAuth extends \OCA\user_external\Base {
+namespace OCA\UserExternal;
+
+class BasicAuth extends Base {
 
 	private $authUrl;
 
@@ -36,14 +38,14 @@ class OC_User_BasicAuth extends \OCA\user_external\Base {
 		);
 		$canary = get_headers($this->authUrl, 1, $context);
 		if(!$canary) {
-			OC::$server->getLogger()->error(
+			\OC::$server->getLogger()->error(
 				'ERROR: Not possible to connect to BasicAuth Url: '.$this->authUrl,
 				['app' => 'user_external']
 			);
 			return false;
 		}
 		if (!isset(array_change_key_case($canary, CASE_LOWER)['www-authenticate'])) {
-			OC::$server->getLogger()->error(
+			\OC::$server->getLogger()->error(
 				'ERROR: Mis-configured BasicAuth Url: '.$this->authUrl.', provided URL does not do authentication!',
 				['app' => 'user_external']
 			);
@@ -60,7 +62,7 @@ class OC_User_BasicAuth extends \OCA\user_external\Base {
 		$headers = get_headers($this->authUrl, 1, $context);
 
 		if(!$headers) {
-			OC::$server->getLogger()->error(
+			\OC::$server->getLogger()->error(
 				'ERROR: Not possible to connect to BasicAuth Url: '.$this->authUrl, 
 				['app' => 'user_external']
 			);
@@ -81,7 +83,7 @@ class OC_User_BasicAuth extends \OCA\user_external\Base {
 				$this->storeUser($uid);
 				return $uid;
 			case "3":
-				OC::$server->getLogger()->error(
+				\OC::$server->getLogger()->error(
 					'ERROR: Too many redirects from BasicAuth Url: '.$this->authUrl, 
 					['app' => 'user_external']
 				);
diff --git a/lib/ftp.php b/lib/FTP.php
similarity index 94%
rename from lib/ftp.php
rename to lib/FTP.php
index ce9ae19..24a4a00 100644
--- a/lib/ftp.php
+++ b/lib/FTP.php
@@ -6,6 +6,8 @@
  * See the COPYING-README file.
  */
 
+namespace OCA\UserExternal;
+
 /**
  * User authentication against a FTP/FTPS server
  *
@@ -15,7 +17,7 @@
  * @license  http://www.gnu.org/licenses/agpl AGPL
  * @link     http://github.com/owncloud/apps
  */
-class OC_User_FTP extends \OCA\user_external\Base{
+class FTP extends Base{
 	private $host;
 	private $secure;
 	private $protocol;
@@ -46,7 +48,7 @@ class OC_User_FTP extends \OCA\user_external\Base{
 	 */
 	public function checkPassword($uid, $password) {
 		if (false === array_search($this->protocol, stream_get_wrappers())) {
-			OC::$server->getLogger()->error(
+			\OC::$server->getLogger()->error(
 				'ERROR: Stream wrapper not available: ' . $this->protocol,
 				['app' => 'user_external']
 			);
diff --git a/lib/imap.php b/lib/IMAP.php
similarity index 96%
rename from lib/imap.php
rename to lib/IMAP.php
index c48fba6..6406782 100644
--- a/lib/imap.php
+++ b/lib/IMAP.php
@@ -7,6 +7,8 @@
  * later.
  * See the COPYING-README file.
  */
+namespace OCA\UserExternal;
+
 
 /**
  * User authentication against an IMAP mail server
@@ -17,7 +19,7 @@
  * @license  http://www.gnu.org/licenses/agpl AGPL
  * @link     http://github.com/owncloud/apps
  */
-class OC_User_IMAP extends \OCA\user_external\Base {
+class IMAP extends Base {
 	private $mailbox;
 	private $port;
 	private $sslmode;
@@ -70,7 +72,7 @@ class OC_User_IMAP extends \OCA\user_external\Base {
 					$uid = $pieces[0];
 				}
 			} else {
-				OC::$server->getLogger()->error(
+				\OC::$server->getLogger()->error(
 					'ERROR: User has a wrong domain! Expecting: '.$this->domain,
 					['app' => 'user_external']
 				);
@@ -105,7 +107,7 @@ class OC_User_IMAP extends \OCA\user_external\Base {
 			$this->storeUser($uid, $groups);
 			return $uid;
 		} else {
-			OC::$server->getLogger()->error(
+			\OC::$server->getLogger()->error(
 				'ERROR: Could not connect to imap server via curl: '.curl_error($ch),
 				['app' => 'user_external']
 			);
diff --git a/lib/smb.php b/lib/SMB.php
similarity index 94%
rename from lib/smb.php
rename to lib/SMB.php
index 49d785d..f5fbe32 100644
--- a/lib/smb.php
+++ b/lib/SMB.php
@@ -5,6 +5,7 @@
  * later.
  * See the COPYING-README file.
  */
+namespace OCA\UserExternal;
 
 /**
  * User authentication via samba (smbclient)
@@ -15,7 +16,7 @@
  * @license  http://www.gnu.org/licenses/agpl AGPL
  * @link     http://github.com/owncloud/apps
  */
-class OC_User_SMB extends \OCA\user_external\Base{
+class SMB extends Base{
 	private $host;
 
 	const SMBCLIENT = 'smbclient -L';
@@ -42,7 +43,7 @@ class OC_User_SMB extends \OCA\user_external\Base{
 		$command = self::SMBCLIENT.' '.escapeshellarg('//' . $this->host . '/dummy').' -U '.$uidEscaped.'%'.$password;
 		$lastline = exec($command, $output, $retval);
 		if ($retval === 127) {
-			OC::$server->getLogger()->error(
+			\OC::$server->getLogger()->error(
 				'ERROR: smbclient executable missing',
 				['app' => 'user_external']
 			);
@@ -55,7 +56,7 @@ class OC_User_SMB extends \OCA\user_external\Base{
 			goto login;
 		} else if ($retval !== 0) {
 			//some other error
-			OC::$server->getLogger()->error(
+			\OC::$server->getLogger()->error(
 				'ERROR: smbclient error: ' . trim($lastline),
 				['app' => 'user_external']
 			);
diff --git a/lib/ssh.php b/lib/SSH.php
similarity index 92%
rename from lib/ssh.php
rename to lib/SSH.php
index 2461b06..5f7212c 100644
--- a/lib/ssh.php
+++ b/lib/SSH.php
@@ -5,6 +5,7 @@
  * later.
  * See the COPYING-README file.
  */
+namespace OCA\UserExternal;
 
 /**
  * User authentication against a SSH server
@@ -17,9 +18,9 @@
  */
 
 
-class OC_User_SSH extends \OCA\user_external\Base {
+class SSH extends Base {
 	private $host;
-  private $port;
+	private $port;
 
 	/**
  	* Create a new SSH authentication provider
@@ -43,7 +44,7 @@ class OC_User_SSH extends \OCA\user_external\Base {
 	*/
 	public function checkPassword($uid, $password) {
 		if (!extension_loaded('ssh2')) {
-			OC::$server->getLogger()->error(
+			\OC::$server->getLogger()->error(
 				'ERROR: php-ssh2 PECL module missing',
 				['app' => 'user_external']
 			);
diff --git a/lib/webdavauth.php b/lib/WebDavAuth.php
similarity index 78%
rename from lib/webdavauth.php
rename to lib/WebDavAuth.php
index 747f9ac..33c8ed0 100644
--- a/lib/webdavauth.php
+++ b/lib/WebDavAuth.php
@@ -6,7 +6,7 @@
  * See the COPYING-README file.
  */
 
-namespace OCA\user_external;
+namespace OCA\UserExternal;
 
 class WebDavAuth extends Base {
 
@@ -28,14 +28,14 @@ class WebDavAuth extends Base {
 	public function checkPassword($uid, $password) {
 		$arr = explode('://', $this->webDavAuthUrl, 2);
 		if( ! isset($arr) OR count($arr) !== 2) {
-			OC::$server->getLogger()->error('ERROR: Invalid WebdavUrl: "'.$this->webDavAuthUrl.'" ', ['app' => 'user_external']);
+			\OC::$server->getLogger()->error('ERROR: Invalid WebdavUrl: "'.$this->webDavAuthUrl.'" ', ['app' => 'user_external']);
 			return false;
 		}
 		list($protocol, $path) = $arr;
 		$url= $protocol.'://'.urlencode($uid).':'.urlencode($password).'@'.$path;
 		$headers = get_headers($url);
 		if($headers === false) {
-			OC::$server->getLogger()->error('ERROR: Not possible to connect to WebDAV Url: "'.$protocol.'://'.$path.'" ', ['app' => 'user_external']);
+			\OC::$server->getLogger()->error('ERROR: Not possible to connect to WebDAV Url: "'.$protocol.'://'.$path.'" ', ['app' => 'user_external']);
 			return false;
 
 		}
diff --git a/lib/xmpp.php b/lib/XMPP.php
similarity index 96%
rename from lib/xmpp.php
rename to lib/XMPP.php
index 3d787ce..c46f888 100644
--- a/lib/xmpp.php
+++ b/lib/XMPP.php
@@ -5,6 +5,7 @@
  * later.
  * See the COPYING-README file.
  */
+namespace OCA\UserExternal;
 
 /**
  * User authentication against a XMPP Prosody MySQL database
@@ -14,7 +15,7 @@
  * @author   Sebastian Sterk https://wiuwiu.de/Imprint
  * @license  http://www.gnu.org/licenses/agpl AGPL
  */
-class OC_User_XMPP extends \OCA\user_external\Base {
+class XMPP extends Base {
 	private $host;
 	private $xmppDb;
 	private $xmppDbUser;
@@ -96,7 +97,7 @@ class OC_User_XMPP extends \OCA\user_external\Base {
 	}
 	
 	public function checkPassword($uid, $password){
-		$pdo = new PDO("mysql:host=$this->host;dbname=$this->xmppDb", $this->xmppDbUser, $this->xmppDbPassword);
+		$pdo = new \PDO("mysql:host=$this->host;dbname=$this->xmppDb", $this->xmppDbUser, $this->xmppDbPassword);
 		if(isset($uid) 
 		   && isset($password)) {
         		if(!filter_var($uid, FILTER_VALIDATE_EMAIL)