diff --git a/apps/files_sharing/ajax/external.php b/apps/files_sharing/ajax/external.php
index f0283d9f268f..baeb8980cd0a 100644
--- a/apps/files_sharing/ajax/external.php
+++ b/apps/files_sharing/ajax/external.php
@@ -122,31 +122,28 @@
 	\OCP\JSON::error(['data' => ['message' => $l->t('Storage not valid')]]);
 	exit();
 }
-$result = $storage->file_exists('');
-if ($result) {
-	try {
-		$storage->getScanner()->scanAll();
-		\OCP\JSON::success();
-	} catch (\OCP\Files\StorageInvalidException $e) {
-		\OCP\Util::writeLog(
-			'files_sharing',
-			'Invalid remote storage: ' . get_class($e) . ': ' . $e->getMessage(),
-			\OCP\Util::DEBUG
-		);
-		\OCP\JSON::error(['data' => ['message' => $l->t('Storage not valid')]]);
-	} catch (\Exception $e) {
+
+try {
+	$result = $storage->file_exists('');
+	if (!$result) {
+		$externalManager->removeShare($mount->getMountPoint());
 		\OCP\Util::writeLog(
 			'files_sharing',
-			'Invalid remote storage: ' . get_class($e) . ': ' . $e->getMessage(),
+			'Couldn\'t add remote share',
 			\OCP\Util::DEBUG
 		);
-		\OCP\JSON::error(['data' => ['message' => $l->t('Couldn\'t add remote share')]]);
 	}
-} else {
-	$externalManager->removeShare($mount->getMountPoint());
+} catch (\OCP\Files\StorageInvalidException $e) {
 	\OCP\Util::writeLog(
 		'files_sharing',
-		'Couldn\'t add remote share',
+		'Invalid remote storage: ' . get_class($e) . ': ' . $e->getMessage(),
+		\OCP\Util::DEBUG
+	);
+	\OCP\JSON::error(['data' => ['message' => $l->t('Storage not valid')]]);
+} catch (\Exception $e) {
+	\OCP\Util::writeLog(
+		'files_sharing',
+		'Invalid remote storage: ' . get_class($e) . ': ' . $e->getMessage(),
 		\OCP\Util::DEBUG
 	);
 	\OCP\JSON::error(['data' => ['message' => $l->t('Couldn\'t add remote share')]]);
diff --git a/apps/files_sharing/ajax/shareinfo.php b/apps/files_sharing/ajax/shareinfo.php
index f2ee72e1dd21..8c2c9663072c 100644
--- a/apps/files_sharing/ajax/shareinfo.php
+++ b/apps/files_sharing/ajax/shareinfo.php
@@ -25,8 +25,17 @@
  *
  */
 
+/**
+ * @deprecated fetches all metadata, kept for compatibility with older instances
+ */
+
 OCP\JSON::checkAppEnabled('files_sharing');
 
+OC::$server->getLogger()->warning(
+	'Deprecated api access from '.OC::$server->getRequest()->getRemoteAddress().
+	'. Ask remote to upgrade.', ['app' => 'files_sharing']
+);
+
 if (!isset($_GET['t'])) {
 	\OC_Response::setStatus(400); //400 Bad Request
 	exit;
@@ -101,4 +110,4 @@ function getChildInfo($dir, $view, $sharePermissions) {
 	$result['children'] = getChildInfo($rootInfo, $rootView, $sharePermissions);
 }
 
-OCP\JSON::success(['data' => $result]);
+OCP\JSON::success(['data' => $result, 'message' => 'DEPRECATED API']);
diff --git a/apps/files_sharing/lib/External/Scanner.php b/apps/files_sharing/lib/External/Scanner.php
deleted file mode 100644
index 782400007d6d..000000000000
--- a/apps/files_sharing/lib/External/Scanner.php
+++ /dev/null
@@ -1,127 +0,0 @@
-<?php
-/**
- * @author Lukas Reschke <lukas@statuscode.ch>
- * @author Morris Jobke <hey@morrisjobke.de>
- * @author Olivier Paroz <github@oparoz.com>
- * @author Robin Appelman <icewind@owncloud.com>
- * @author Vincent Petry <pvince81@owncloud.com>
- *
- * @copyright Copyright (c) 2017, ownCloud GmbH
- * @license AGPL-3.0
- *
- * This code is free software: you can redistribute it and/or modify
- * it under the terms of the GNU Affero General Public License, version 3,
- * as published by the Free Software Foundation.
- *
- * 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, version 3,
- * along with this program.  If not, see <http://www.gnu.org/licenses/>
- *
- */
-
-namespace OCA\Files_Sharing\External;
-
-use OC\ForbiddenException;
-use OCP\Files\NotFoundException;
-use OCP\Files\StorageInvalidException;
-use OCP\Files\StorageNotAvailableException;
-
-class Scanner extends \OC\Files\Cache\Scanner {
-	/** @var \OCA\Files_Sharing\External\Storage */
-	protected $storage;
-
-	/** {@inheritDoc} */
-	public function scan($path, $recursive = self::SCAN_RECURSIVE, $reuse = -1, $lock = true) {
-		if(!$this->storage->remoteIsOwnCloud()) {
-			return parent::scan($path, $recursive, $recursive, $lock);
-		}
-
-		$this->scanAll();
-	}
-
-	/**
-	 * Scan a single file and store it in the cache.
-	 * If an exception happened while accessing the external storage,
-	 * the storage will be checked for availability and removed
-	 * if it is not available any more.
-	 *
-	 * @param string $file file to scan
-	 * @param int $reuseExisting
-	 * @param int $parentId
-	 * @param array | null $cacheData existing data in the cache for the file to be scanned
-	 * @param bool $lock set to false to disable getting an additional read lock during scanning
-	 * @return array an array of metadata of the scanned file
-	 */
-	public function scanFile($file, $reuseExisting = 0, $parentId = -1, $cacheData = null, $lock = true) {
-		try {
-			return parent::scanFile($file, $reuseExisting);
-		} catch (ForbiddenException $e) {
-			$this->storage->checkStorageAvailability();
-		} catch (NotFoundException $e) {
-			// if the storage isn't found, the call to
-			// checkStorageAvailable() will verify it and remove it
-			// if appropriate
-			$this->storage->checkStorageAvailability();
-		} catch (StorageInvalidException $e) {
-			$this->storage->checkStorageAvailability();
-		} catch (StorageNotAvailableException $e) {
-			$this->storage->checkStorageAvailability();
-		}
-	}
-
-	/**
-	 * Checks the remote share for changes.
-	 * If changes are available, scan them and update
-	 * the cache.
-	 * @throws NotFoundException
-	 * @throws StorageInvalidException
-	 * @throws \Exception
-	 */
-	public function scanAll() {
-		try {
-			$data = $this->storage->getShareInfo();
-		} catch (\Exception $e) {
-			$this->storage->checkStorageAvailability();
-			throw new \Exception(
-				'Error while scanning remote share: "' .
-				$this->storage->getRemote() . '" ' .
-				$e->getMessage()
-			);
-		}
-		if ($data['status'] === 'success') {
-			$this->addResult($data['data'], '');
-		} else {
-			throw new \Exception(
-				'Error while scanning remote share: "' .
-				$this->storage->getRemote() . '"'
-			);
-		}
-	}
-
-	/**
-	 * @param array $data
-	 * @param string $path
-	 */
-	private function addResult($data, $path) {
-		$id = $this->cache->put($path, $data);
-		if (isset($data['children'])) {
-			$children = [];
-			foreach ($data['children'] as $child) {
-				$children[$child['name']] = true;
-				$this->addResult($child, ltrim($path . '/' . $child['name'], '/'));
-			}
-
-			$existingCache = $this->cache->getFolderContentsById($id);
-			foreach ($existingCache as $existingChild) {
-				// if an existing child is not in the new data, remove it
-				if (!isset($children[$existingChild['name']])) {
-					$this->cache->remove(ltrim($path . '/' . $existingChild['name'], '/'));
-				}
-			}
-		}
-	}
-}
diff --git a/apps/files_sharing/lib/External/Storage.php b/apps/files_sharing/lib/External/Storage.php
index 822f46ad66b7..49a599282c01 100644
--- a/apps/files_sharing/lib/External/Storage.php
+++ b/apps/files_sharing/lib/External/Storage.php
@@ -30,13 +30,11 @@
 use GuzzleHttp\Exception\ClientException;
 use GuzzleHttp\Exception\ConnectException;
 use OC\Files\Storage\DAV;
-use OC\ForbiddenException;
 use OCA\FederatedFileSharing\DiscoveryManager;
 use OCA\Files_Sharing\ISharedStorage;
-use OCP\AppFramework\Http;
-use OCP\Files\NotFoundException;
 use OCP\Files\StorageInvalidException;
 use OCP\Files\StorageNotAvailableException;
+use Sabre\DAV\Client;
 
 class Storage extends DAV implements ISharedStorage {
 	/** @var string */
@@ -89,7 +87,9 @@ public function __construct($options) {
 			'host' => $host,
 			'root' => $root,
 			'user' => $options['token'],
-			'password' => (string)$options['password']
+			'password' => (string)$options['password'],
+			// Federated sharing always uses BASIC auth
+			'authType' => Client::AUTH_BASIC
 		]);
 	}
 
@@ -139,21 +139,6 @@ public function getCache($path = '', $storage = null) {
 		return $this->cache;
 	}
 
-	/**
-	 * @param string $path
-	 * @param \OC\Files\Storage\Storage $storage
-	 * @return \OCA\Files_Sharing\External\Scanner
-	 */
-	public function getScanner($path = '', $storage = null) {
-		if (!$storage) {
-			$storage = $this;
-		}
-		if (!isset($this->scanner)) {
-			$this->scanner = new Scanner($storage);
-		}
-		return $this->scanner;
-	}
-
 	/**
 	 * check if a file or folder has been updated since $time
 	 *
@@ -207,29 +192,25 @@ public function test() {
 	public function checkStorageAvailability() {
 		// see if we can find out why the share is unavailable
 		try {
-			$this->getShareInfo();
-		} catch (NotFoundException $e) {
-			// a 404 can either mean that the share no longer exists or there is no ownCloud on the remote
-			if ($this->testRemote()) {
-				// valid ownCloud instance means that the public share no longer exists
-				// since this is permanent (re-sharing the file will create a new token)
-				// we remove the invalid storage
-				$this->manager->removeShare($this->mountPoint);
-				$this->manager->getMountManager()->removeMount($this->mountPoint);
-				throw new StorageInvalidException();
-			} else {
-				// ownCloud instance is gone, likely to be a temporary server configuration error
-				throw new StorageNotAvailableException();
+			if ( ! $this->propfind('') ) {
+				// a 404 can either mean that the share no longer exists or there is no ownCloud on the remote
+				if ($this->testRemote()) {
+					// valid ownCloud instance means that the public share no longer exists
+					// since this is permanent (re-sharing the file will create a new token)
+					// we remove the invalid storage
+					$this->manager->removeShare($this->mountPoint);
+					$this->manager->getMountManager()->removeMount($this->mountPoint);
+					throw new StorageInvalidException();
+				} else {
+					// ownCloud instance is gone, likely to be a temporary server configuration error
+					throw new StorageNotAvailableException();
+				}
 			}
-		} catch (ForbiddenException $e) {
+		} catch (StorageInvalidException $e) {
 			// auth error, remove share for now (provide a dialog in the future)
 			$this->manager->removeShare($this->mountPoint);
 			$this->manager->getMountManager()->removeMount($this->mountPoint);
-			throw new StorageInvalidException();
-		} catch (\GuzzleHttp\Exception\ConnectException $e) {
-			throw new StorageNotAvailableException();
-		} catch (\GuzzleHttp\Exception\RequestException $e) {
-			throw new StorageNotAvailableException();
+			throw $e;
 		} catch (\Exception $e) {
 			throw $e;
 		}
@@ -286,61 +267,6 @@ private function testRemoteUrl($url) {
 		return $returnValue;
 	}
 
-	/**
-	 * Whether the remote is an ownCloud, used since some sharing features are not
-	 * standardized. Let's use this to detect whether to use it.
-	 *
-	 * @return bool
-	 */
-	public function remoteIsOwnCloud() {
-		if(defined('PHPUNIT_RUN') || !$this->testRemoteUrl($this->getRemote() . '/status.php')) {
-			return false;
-		}
-		return true;
-	}
-
-	/**
-	 * @return mixed
-	 * @throws ForbiddenException
-	 * @throws NotFoundException
-	 * @throws \Exception
-	 */
-	public function getShareInfo() {
-		$remote = $this->getRemote();
-		$token = $this->getToken();
-		$password = $this->getPassword();
-
-		// If remote is not an ownCloud do not try to get any share info
-		if(!$this->remoteIsOwnCloud()) {
-			return ['status' => 'unsupported'];
-		}
-
-		$url = rtrim($remote, '/') . '/index.php/apps/files_sharing/shareinfo?t=' . $token;
-
-		// TODO: DI
-		$client = \OC::$server->getHTTPClientService()->newClient();
-		try {
-			$response = $client->post($url, [
-				'body' => ['password' => $password],
-				'timeout' => 10,
-				'connect_timeout' => 10,
-			]);
-		} catch (\GuzzleHttp\Exception\RequestException $e) {
-			if ($e->getCode() === Http::STATUS_UNAUTHORIZED || $e->getCode() === Http::STATUS_FORBIDDEN) {
-				throw new ForbiddenException();
-			}
-			if ($e->getCode() === Http::STATUS_NOT_FOUND) {
-				throw new NotFoundException();
-			}
-			// throw this to be on the safe side: the share will still be visible
-			// in the UI in case the failure is intermittent, and the user will
-			// be able to decide whether to remove it if it's really gone
-			throw new StorageNotAvailableException();
-		}
-
-		return json_decode($response->getBody(), true);
-	}
-
 	public function getOwner($path) {
 		list(, $remote) = explode('://', $this->remote, 2);
 		return $this->remoteUser . '@' . $remote;
diff --git a/apps/files_sharing/tests/External/ScannerTest.php b/apps/files_sharing/tests/External/ScannerTest.php
deleted file mode 100644
index c2da2705b7f1..000000000000
--- a/apps/files_sharing/tests/External/ScannerTest.php
+++ /dev/null
@@ -1,82 +0,0 @@
-<?php
-/**
- * @author Joas Schilling <coding@schilljs.com>
- *
- * @copyright Copyright (c) 2017, ownCloud GmbH
- * @license AGPL-3.0
- *
- * This code is free software: you can redistribute it and/or modify
- * it under the terms of the GNU Affero General Public License, version 3,
- * as published by the Free Software Foundation.
- *
- * 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, version 3,
- * along with this program.  If not, see <http://www.gnu.org/licenses/>
- *
- */
-
-namespace OCA\Files_Sharing\Tests\External;
-
-use OCA\Files_Sharing\External\Scanner;
-use Test\TestCase;
-
-class ScannerTest extends TestCase {
-	/** @var \OCA\Files_Sharing\External\Scanner */
-	protected $scanner;
-	/** @var \OCA\Files_Sharing\External\Storage|\PHPUnit_Framework_MockObject_MockObject */
-	protected $storage;
-	/** @var \OC\Files\Cache\Cache|\PHPUnit_Framework_MockObject_MockObject */
-	protected $cache;
-
-	protected function setUp() {
-		parent::setUp();
-
-		$this->storage = $this->getMockBuilder('\OCA\Files_Sharing\External\Storage')
-			->disableOriginalConstructor()
-			->getMock();
-		$this->cache = $this->getMockBuilder('\OC\Files\Cache\Cache')
-			->disableOriginalConstructor()
-			->getMock();
-		$this->storage->expects($this->any())
-			->method('getCache')
-			->willReturn($this->cache);
-
-		$this->scanner = new Scanner($this->storage);
-	}
-
-	public function testScanAll() {
-		$this->storage->expects($this->any())
-			->method('getShareInfo')
-			->willReturn(['status' => 'success', 'data' => []]);
-
-		// FIXME add real tests, we are currently only checking for
-		// Declaration of OCA\Files_Sharing\External\Scanner::*() should be
-		// compatible with OC\Files\Cache\Scanner::*()
-		$this->scanner->scanAll();
-		$this->assertTrue(true);
-	}
-
-	public function testScan() {
-		$this->storage->expects($this->any())
-			->method('getShareInfo')
-			->willReturn(['status' => 'success', 'data' => []]);
-
-		// FIXME add real tests, we are currently only checking for
-		// Declaration of OCA\Files_Sharing\External\Scanner::*() should be
-		// compatible with OC\Files\Cache\Scanner::*()
-		$this->scanner->scan('test', Scanner::SCAN_RECURSIVE);
-		$this->assertTrue(true);
-	}
-
-	public function testScanFile() {
-		// FIXME add real tests, we are currently only checking for
-		// Declaration of OCA\Files_Sharing\External\Scanner::*() should be
-		// compatible with OC\Files\Cache\Scanner::*()
-		$this->scanner->scanFile('test', Scanner::SCAN_RECURSIVE);
-		$this->assertTrue(true);
-	}
-}
diff --git a/lib/private/Files/Storage/DAV.php b/lib/private/Files/Storage/DAV.php
index dd987f2c202e..36b39cfbfe37 100644
--- a/lib/private/Files/Storage/DAV.php
+++ b/lib/private/Files/Storage/DAV.php
@@ -273,7 +273,7 @@ protected function propfind($path) {
 				);
 				$this->statCache->set($path, $response);
 			} catch (ClientHttpException $e) {
-				if ($e->getHttpStatus() === 404) {
+				if ($e->getHttpStatus() === Http::STATUS_NOT_FOUND) {
 					$this->statCache->clear($path . '/');
 					$this->statCache->set($path, false);
 					return false;
@@ -352,7 +352,7 @@ public function fopen($path, $mode) {
 							]);
 				} catch (RequestException $e) {
 					if ($e->getResponse() instanceof ResponseInterface
-						&& $e->getResponse()->getStatusCode() === 404) {
+						&& $e->getResponse()->getStatusCode() === Http::STATUS_NOT_FOUND) {
 						return false;
 					} else {
 						throw $e;
@@ -656,7 +656,7 @@ private function simpleResponse($method, $path, $body, $expected) {
 			$response = $this->client->request($method, $this->encodePath($path), $body);
 			return $response['statusCode'] == $expected;
 		} catch (ClientHttpException $e) {
-			if ($e->getHttpStatus() === 404 && $method === 'DELETE') {
+			if ($e->getHttpStatus() === Http::STATUS_NOT_FOUND && $method === 'DELETE') {
 				$this->statCache->clear($path . '/');
 				$this->statCache->set($path, false);
 				return false;
@@ -769,7 +769,7 @@ public function hasUpdated($path, $time) {
 			if ($response === false) {
 				if ($path === '') {
 					// if root is gone it means the storage is not available
-					throw new StorageNotAvailableException(get_class($e) . ': ' . $e->getMessage());
+					throw new StorageNotAvailableException('remote root vanished');
 				}
 				return false;
 			}