diff --git a/CHANGELOG.md b/CHANGELOG.md
index 4ea9683b..6039aeb1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,30 @@
 
 All notable changes to this project will be documented in this file, in reverse chronological order by release.
 
+## 1.8.7 - TBD
+
+### Added
+
+- Nothing.
+
+### Changed
+
+- Nothing.
+
+### Deprecated
+
+- Nothing.
+
+### Removed
+
+- Nothing.
+
+### Fixed
+
+- [#364](https://github.com/zendframework/zend-diactoros/issues/364) modifies detection of HTTPS schemas via the `$_SERVER['HTTPS']` value
+  such that an empty HTTPS-key will result in a scheme of `http` and not
+  `https`.
+
 ## 1.8.6 - 2018-09-05
 
 ### Added
diff --git a/src/functions/marshal_uri_from_sapi.php b/src/functions/marshal_uri_from_sapi.php
index decaafb8..eba3d1ec 100644
--- a/src/functions/marshal_uri_from_sapi.php
+++ b/src/functions/marshal_uri_from_sapi.php
@@ -171,7 +171,7 @@ function marshalUriFromSapi(array $server, array $headers)
     } else {
         $https = false;
     }
-    if (($https && 'off' !== strtolower($https))
+    if (($https && 'on' === strtolower($https))
         || strtolower($getHeaderFromArray('x-forwarded-proto', $headers, false)) === 'https'
     ) {
         $scheme = 'https';
diff --git a/test/ServerRequestFactoryTest.php b/test/ServerRequestFactoryTest.php
index 003b8aec..fded011d 100644
--- a/test/ServerRequestFactoryTest.php
+++ b/test/ServerRequestFactoryTest.php
@@ -295,7 +295,7 @@ public function testMarshalUriDetectsHttpsSchemeFromServerValue($param)
         $request = $request->withHeader('Host', 'example.com');
 
         $server  = [
-            $param => true,
+            $param => 'on',
         ];
 
         $uri = marshalUriFromSapi($server, $request->getHeaders());
diff --git a/test/functions/MarshalUriFromSapiTest.php b/test/functions/MarshalUriFromSapiTest.php
new file mode 100644
index 00000000..708522d3
--- /dev/null
+++ b/test/functions/MarshalUriFromSapiTest.php
@@ -0,0 +1,77 @@
+<?php
+/**
+ * @see       https://github.com/zendframework/zend-diactoros for the canonical source repository
+ * @copyright Copyright (c) 2019 Zend Technologies USA Inc. (http://www.zend.com)
+ * @license   https://github.com/zendframework/zend-diactoros/blob/master/LICENSE.md New BSD License
+ */
+
+namespace ZendTest\Diactoros\functions;
+
+use PHPUnit\Framework\TestCase;
+use function Zend\Diactoros\marshalUriFromSapi;
+
+class MarshalUriFromSapiTest extends TestCase
+{
+    /**
+     * @param string $httpsValue
+     * @param string $expectedScheme
+     * @dataProvider returnsUrlWithCorrectHttpSchemeFromArraysProvider
+     */
+    public function testReturnsUrlWithCorrectHttpSchemeFromArrays($httpsValue, $expectedScheme)
+    {
+        $server = [
+            'HTTPS' => $httpsValue,
+            'SERVER_NAME' => 'localhost',
+            'SERVER_PORT' => '80',
+            'SERVER_ADDR' => '172.22.0.4',
+            'REMOTE_PORT' => '36852',
+            'REMOTE_ADDR' => '172.22.0.1',
+            'SERVER_SOFTWARE' => 'nginx/1.11.8',
+            'GATEWAY_INTERFACE' => 'CGI/1.1',
+            'SERVER_PROTOCOL' => 'HTTP/1.1',
+            'DOCUMENT_ROOT' => '/var/www/public',
+            'DOCUMENT_URI' => '/index.php',
+            'REQUEST_URI' => '/api/messagebox-schema',
+            'PATH_TRANSLATED' => '/var/www/public',
+            'PATH_INFO' => '',
+            'SCRIPT_NAME' => '/index.php',
+            'CONTENT_LENGTH' => '',
+            'CONTENT_TYPE' => '',
+            'REQUEST_METHOD' => 'GET',
+            'QUERY_STRING' => '',
+            'SCRIPT_FILENAME' => '/var/www/public/index.php',
+            'FCGI_ROLE' => 'RESPONDER',
+            'PHP_SELF' => '/index.php',
+        ];
+
+        $headers = [
+            'HTTP_COOKIE' => '',
+            'HTTP_ACCEPT_LANGUAGE' => 'de-DE,de;q=0.9,en-US;q=0.8,en;q=0.7',
+            'HTTP_ACCEPT_ENCODING' => 'gzip, deflate, br',
+            'HTTP_REFERER' => 'http://localhost:8080/index.html',
+            'HTTP_USER_AGENT' => 'Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko)',
+            'HTTP_ACCEPT' => 'application/json,*/*',
+            'HTTP_CONNECTION' => 'keep-alive',
+            'HTTP_HOST' => 'localhost:8080',
+        ];
+
+        $url = marshalUriFromSapi($server, $headers);
+
+        self::assertSame($expectedScheme, $url->getScheme());
+    }
+
+    /**
+     * @return array
+     */
+    public function returnsUrlWithCorrectHttpSchemeFromArraysProvider()
+    {
+        return [
+            'on-lowercase' => ['on', 'https'],
+            'on-uppercase' => ['ON', 'https'],
+            'off-lowercase' => ['off', 'http'],
+            'off-mixed-case' => ['oFf', 'http'],
+            'neither-on-nor-off' => ['foo', 'http'],
+            'empty' => ['', 'http'],
+        ];
+    }
+}