diff --git a/apps/files/appinfo/remote.php b/apps/files/appinfo/remote.php
index 1e54fc10efaef64824d595770f4fc5a7a8d49a1d..b8dc68f1f811f9d09364ebc6e91633baa9b38d4a 100644
--- a/apps/files/appinfo/remote.php
+++ b/apps/files/appinfo/remote.php
@@ -43,6 +43,7 @@ $server->setBaseUri($baseuri);
// Load plugins
$defaults = new OC_Defaults();
+$server->addPlugin(new \OC\Connector\Sabre\BlockLegacyClientPlugin(\OC::$server->getConfig()));
$server->addPlugin(new \Sabre\DAV\Auth\Plugin($authBackend, $defaults->getName()));
// FIXME: The following line is a workaround for legacy components relying on being able to send a GET to /
$server->addPlugin(new \OC\Connector\Sabre\DummyGetResponsePlugin());
diff --git a/config/config.sample.php b/config/config.sample.php
index 61ae59542d431bd4dc0fa2c508cc37a8a314f5d4..e0e4a3cae976c1c6ab541926a9c4aea7bca0fdac 100644
--- a/config/config.sample.php
+++ b/config/config.sample.php
@@ -799,6 +799,14 @@ $CONFIG = array(
*/
'cipher' => 'AES-256-CFB',
+/**
+ * The minimum ownCloud desktop client version that is required to sync with
+ * this instance. Defaults to the official supported releases by ownCloud.
+ *
+ * When adjusting this please be aware of the fact that older versions may
+ * be buggy and for best user experience we recommend setting
+ */
+'minimum.supported.desktop.version' => '1.7.0',
/**
* Memory caching backend configuration
diff --git a/lib/private/connector/sabre/blocklegacyclientplugin.php b/lib/private/connector/sabre/blocklegacyclientplugin.php
new file mode 100644
index 0000000000000000000000000000000000000000..4d595b5f6de9dbd13cc02af64120877ba2a09d07
--- /dev/null
+++ b/lib/private/connector/sabre/blocklegacyclientplugin.php
@@ -0,0 +1,76 @@
+<?php
+/**
+ * @author Lukas Reschke <lukas@owncloud.com>
+ *
+ * @copyright Copyright (c) 2015, ownCloud, Inc.
+ * @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 OC\Connector\Sabre;
+
+use OC\ServiceUnavailableException;
+use OCP\IConfig;
+use Sabre\HTTP\RequestInterface;
+use Sabre\DAV\ServerPlugin;
+use Sabre\DAV\Server;
+
+/**
+ * Class BlockLegacyClientPlugin is used to detect old legacy sync clients and
+ * returns a 503 status to those clients.
+ *
+ * @package OC\Connector\Sabre
+ */
+class BlockLegacyClientPlugin extends ServerPlugin {
+ /** @var Server */
+ protected $server;
+ /** @var IConfig */
+ protected $config;
+
+ /**
+ * @param IConfig $config
+ */
+ public function __construct(IConfig $config) {
+ $this->config = $config;
+ }
+
+ /**
+ * @param Server $server
+ * @return void
+ */
+ public function initialize(Server $server) {
+ $this->server = $server;
+ $this->server->on('beforeMethod', [$this, 'beforeHandler'], 200);
+ }
+
+ /**
+ * Detects all unsupported clients and throws a ServiceUnavailableException
+ * which will result in a 503 to them.
+ * @param RequestInterface $request
+ * @throws ServiceUnavailableException If the client version is not supported
+ */
+ public function beforeHandler(RequestInterface $request) {
+ $userAgent = $request->getHeader('User-Agent');
+ $minimumSupportedDesktopVersion = $this->config->getSystemValue('minimum.supported.desktop.version', '1.7.0');
+
+ // Match on the mirall version which is in scheme "Mozilla/5.0 (%1) mirall/%2" or
+ // "mirall/%1" for older releases
+ preg_match("/(?:mirall\\/)([\d.]+)/i", $userAgent, $versionMatches);
+ if(isset($versionMatches[1]) &&
+ version_compare($versionMatches[1], $minimumSupportedDesktopVersion) === -1) {
+ throw new ServiceUnavailableException('Unsupported client version.');
+ }
+ }
+}
diff --git a/tests/lib/connector/sabre/BlockLegacyClientPluginTest.php b/tests/lib/connector/sabre/BlockLegacyClientPluginTest.php
new file mode 100644
index 0000000000000000000000000000000000000000..ed735f068494960d364a708d6a27c6cf4770c9f5
--- /dev/null
+++ b/tests/lib/connector/sabre/BlockLegacyClientPluginTest.php
@@ -0,0 +1,117 @@
+<?php
+/**
+ * @author Lukas Reschke <lukas@owncloud.com>
+ *
+ * @copyright Copyright (c) 2015, ownCloud, Inc.
+ * @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 Test\Connector\Sabre;
+
+use OC\Connector\Sabre\BlockLegacyClientPlugin;
+use Test\TestCase;
+use OCP\IConfig;
+
+/**
+ * Class BlockLegacyClientPluginTest
+ *
+ * @package Test\Connector\Sabre
+ */
+class BlockLegacyClientPluginTest extends TestCase {
+ /** @var IConfig */
+ private $config;
+ /** @var BlockLegacyClientPlugin */
+ private $blockLegacyClientVersionPlugin;
+
+ public function setUp() {
+ parent::setUp();
+
+ $this->config = $this->getMock('\OCP\IConfig');
+ $this->blockLegacyClientVersionPlugin = new BlockLegacyClientPlugin($this->config);
+ }
+
+ /**
+ * @return array
+ */
+ public function oldDesktopClientProvider() {
+ return [
+ ['Mozilla/5.0 (1.5.0) mirall/1.5.0'],
+ ['mirall/1.5.0'],
+ ['mirall/1.5.4'],
+ ['mirall/1.6.0'],
+ ['Mozilla/5.0 (Bogus Text) mirall/1.6.9'],
+ ];
+ }
+
+ /**
+ * @dataProvider oldDesktopClientProvider
+ * @param string $userAgent
+ * @expectedException \OC\ServiceUnavailableException
+ * @expectedExceptionMessage Unsupported client version.
+ */
+ public function testBeforeHandlerException($userAgent) {
+ /** @var \Sabre\HTTP\RequestInterface $request */
+ $request = $this->getMock('\Sabre\HTTP\RequestInterface');
+ $request
+ ->expects($this->once())
+ ->method('getHeader')
+ ->with('User-Agent')
+ ->will($this->returnValue($userAgent));
+
+ $this->config
+ ->expects($this->once())
+ ->method('getSystemValue')
+ ->with('minimum.supported.desktop.version', '1.7.0')
+ ->will($this->returnValue('1.7.0'));
+
+ $this->blockLegacyClientVersionPlugin->beforeHandler($request);
+ }
+
+ /**
+ * @return array
+ */
+ public function newAndAlternateDesktopClientProvider() {
+ return [
+ ['Mozilla/5.0 (1.7.0) mirall/1.7.0'],
+ ['mirall/1.8.3'],
+ ['mirall/1.7.2'],
+ ['mirall/1.7.0'],
+ ['Mozilla/5.0 (Bogus Text) mirall/1.9.3'],
+ ];
+ }
+
+ /**
+ * @dataProvider newAndAlternateDesktopClientProvider
+ * @param string $userAgent
+ */
+ public function testBeforeHandlerSucess($userAgent) {
+ /** @var \Sabre\HTTP\RequestInterface $request */
+ $request = $this->getMock('\Sabre\HTTP\RequestInterface');
+ $request
+ ->expects($this->once())
+ ->method('getHeader')
+ ->with('User-Agent')
+ ->will($this->returnValue($userAgent));
+
+ $this->config
+ ->expects($this->once())
+ ->method('getSystemValue')
+ ->with('minimum.supported.desktop.version', '1.7.0')
+ ->will($this->returnValue('1.7.0'));
+
+ $this->blockLegacyClientVersionPlugin->beforeHandler($request);
+ }
+
+}