diff --git a/lib/private/Remote/Instance.php b/lib/private/Remote/Instance.php
index 0ed301ae86..3e77226eda 100644
--- a/lib/private/Remote/Instance.php
+++ b/lib/private/Remote/Instance.php
@@ -97,19 +97,26 @@ class Instance implements IInstance {
 	/**
 	 * @return array
 	 * @throws NotFoundException
+	 * @throws \Exception
 	 */
 	private function getStatus() {
 		if ($this->status) {
 			return $this->status;
 		}
 		$key = 'remote/' . $this->url . '/status';
+		$httpsKey = 'remote/' . $this->url . '/https';
 		$status = $this->cache->get($key);
 		if (!$status) {
 			$response = $this->downloadStatus('https://' . $this->getUrl() . '/status.php');
 			$protocol = 'https';
 			if (!$response) {
+				if ($status = $this->cache->get($httpsKey)) {
+					throw new \Exception('refusing to connect to remote instance(' . $this->url . ') over http that was previously accessible over https');
+				}
 				$response = $this->downloadStatus('http://' . $this->getUrl() . '/status.php');
 				$protocol = 'http';
+			} else {
+				$this->cache->set($httpsKey, true, 60 * 60 * 24 * 365);
 			}
 			$status = json_decode($response, true);
 			if ($status) {
diff --git a/tests/lib/Remote/InstanceTest.php b/tests/lib/Remote/InstanceTest.php
new file mode 100644
index 0000000000..5cce232309
--- /dev/null
+++ b/tests/lib/Remote/InstanceTest.php
@@ -0,0 +1,128 @@
+<?php
+/**
+ * @copyright Copyright (c) 2017 Robin Appelman <robin@icewind.nl>
+ *
+ * @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 Test\Remote;
+
+
+use OC\Memcache\ArrayCache;
+use OC\Remote\Instance;
+use OCP\Http\Client\IClient;
+use OCP\Http\Client\IClientService;
+use OCP\Http\Client\IResponse;
+use OCP\ICache;
+use Test\TestCase;
+
+class InstanceTest extends TestCase {
+	/** @var IClientService|\PHPUnit_Framework_MockObject_MockObject */
+	private $clientService;
+	/** @var IClient|\PHPUnit_Framework_MockObject_MockObject */
+	private $client;
+	/** @var ICache */
+	private $cache;
+	private $expectedRequests = [];
+
+	protected function setUp() {
+		parent::setUp();
+
+		$this->cache = new ArrayCache();
+
+		$this->clientService = $this->createMock(IClientService::class);
+		$this->client = $this->createMock(IClient::class);
+		$this->clientService->expects($this->any())
+			->method('newClient')
+			->willReturn($this->client);
+		$this->client->expects($this->any())
+			->method('get')
+			->willReturnCallback(function ($url) {
+				if (!isset($this->expectedRequests[$url])) {
+					throw new \Exception('unexpected request');
+				}
+				$result = $this->expectedRequests[$url];
+
+				if ($result instanceof \Exception) {
+					throw $result;
+				} else {
+					$response = $this->createMock(IResponse::class);
+					$response->expects($this->any())
+						->method('getBody')
+						->willReturn($result);
+					return $response;
+				}
+			});
+	}
+
+	/**
+	 * @param string $url
+	 * @param string|\Exception $result
+	 */
+	protected function expectRequest($url, $result) {
+		$this->expectedRequests[$url] = $result;
+	}
+
+	public function testBasicStatus() {
+		$instance = new Instance('example.com', $this->cache, $this->clientService);
+		$this->expectRequest('https://example.com/status.php', '{"installed":true,"maintenance":false,"needsDbUpgrade":false,"version":"13.0.0.5","versionstring":"13.0.0 alpha","edition":"","productname":"Nextcloud"}');
+
+		$this->assertEquals(true, $instance->isActive());
+		$this->assertEquals('13.0.0.5', $instance->getVersion());
+		$this->assertEquals('https', $instance->getProtocol());
+		$this->assertEquals('https://example.com', $instance->getFullUrl());
+	}
+
+	public function testHttpFallback() {
+		$instance = new Instance('example.com', $this->cache, $this->clientService);
+		$this->expectRequest('https://example.com/status.php', new \Exception());
+		$this->expectRequest('http://example.com/status.php', '{"installed":true,"maintenance":false,"needsDbUpgrade":false,"version":"13.0.0.5","versionstring":"13.0.0 alpha","edition":"","productname":"Nextcloud"}');
+
+		$this->assertEquals('http', $instance->getProtocol());
+		$this->assertEquals('http://example.com', $instance->getFullUrl());
+	}
+
+	public function testRerequestHttps() {
+		$instance = new Instance('example.com', $this->cache, $this->clientService);
+		$this->expectRequest('https://example.com/status.php', '{"installed":true,"maintenance":false,"needsDbUpgrade":false,"version":"13.0.0.5","versionstring":"13.0.0 alpha","edition":"","productname":"Nextcloud"}');
+
+		$this->assertEquals('https', $instance->getProtocol());
+		$this->assertEquals(true, $instance->isActive());
+
+		$this->cache->remove('remote/example.com/status');
+		$this->expectRequest('https://example.com/status.php', '{"installed":true,"maintenance":true,"needsDbUpgrade":false,"version":"13.0.0.5","versionstring":"13.0.0 alpha","edition":"","productname":"Nextcloud"}');
+		$instance2 = new Instance('example.com', $this->cache, $this->clientService);
+		$this->assertEquals('https', $instance2->getProtocol());
+		$this->assertEquals(false, $instance2->isActive());
+	}
+
+	/**
+	 * @expectedException \Exception
+	 * @expectedExceptionMessage refusing to connect to remote instance(example.com) over http that was previously accessible over https
+	 */
+	public function testPreventDowngradeAttach() {
+		$instance = new Instance('example.com', $this->cache, $this->clientService);
+		$this->expectRequest('https://example.com/status.php', '{"installed":true,"maintenance":false,"needsDbUpgrade":false,"version":"13.0.0.5","versionstring":"13.0.0 alpha","edition":"","productname":"Nextcloud"}');
+
+		$this->assertEquals('https', $instance->getProtocol());
+
+		$this->expectRequest('https://example.com/status.php', new \Exception());
+		$this->cache->remove('remote/example.com/status');
+		$instance2 = new Instance('example.com', $this->cache, $this->clientService);
+		$instance2->getProtocol();
+	}
+}