diff -u b/core/composer.json b/core/composer.json
--- b/core/composer.json
+++ b/core/composer.json
@@ -13,7 +13,7 @@
     "symfony/event-dispatcher": "2.6.*",
     "symfony/http-foundation": "2.6.*",
     "symfony/http-kernel": "2.6.*",
-    "symfony/psr-http-message-bridge": "dev-master",
+    "symfony/psr-http-message-bridge": "v0.1",
     "symfony/routing": "2.6.*",
     "symfony/serializer": "2.6.*",
     "symfony/validator": "2.6.*@dev",
@@ -27,7 +27,7 @@
     "easyrdf/easyrdf": "0.9.*",
     "phpunit/phpunit": "4.6.*",
     "zendframework/zend-feed": "2.4.*",
-    "zendframework/zend-diactoros": "1.0.*@dev",
+    "zendframework/zend-diactoros": "1.0.*",
     "mikey179/vfsStream": "1.*",
     "stack/builder": "1.0.*",
     "egulias/email-validator": "1.2.*",
diff -u b/core/composer.lock b/core/composer.lock
--- b/core/composer.lock
+++ b/core/composer.lock
@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#composer-lock-the-lock-file",
         "This file is @generated automatically"
     ],
-    "hash": "94abda0d0957e082ea0a6b0a14d38d41",
+    "hash": "58ab0c87f9cddc47eb8b576cfb439d02",
     "packages": [
         {
             "name": "behat/mink",
@@ -2828,7 +2828,7 @@
         },
         {
             "name": "symfony/psr-http-message-bridge",
-            "version": "dev-master",
+            "version": "v0.1",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/psr-http-message-bridge.git",
@@ -3239,7 +3239,7 @@
         },
         {
             "name": "zendframework/zend-diactoros",
-            "version": "dev-master",
+            "version": "1.0.1",
             "source": {
                 "type": "git",
                 "url": "https://github.com/zendframework/zend-diactoros.git",
@@ -3441,9 +3441,7 @@
     "aliases": [],
     "minimum-stability": "stable",
     "stability-flags": {
-        "symfony/psr-http-message-bridge": 20,
-        "symfony/validator": 20,
-        "zendframework/zend-diactoros": 20
+        "symfony/validator": 20
     },
     "prefer-stable": false,
     "prefer-lowest": false,
diff -u b/core/core.services.yml b/core/core.services.yml
--- b/core/core.services.yml
+++ b/core/core.services.yml
@@ -597,9 +597,9 @@
       - { name: http_middleware, priority: 50 }
     calls:
       - [setContainer, ['@service_container']]
-  http_foundation.factory:
+  psr7_foundation.factory:
     class: Symfony\Bridge\PsrHttpMessage\Factory\HttpFoundationFactory
-  diactoros.factory:
+  psr7_diactoros.factory:
     class: Symfony\Bridge\PsrHttpMessage\Factory\DiactorosFactory
   language_manager:
     class: Drupal\Core\Language\LanguageManager
diff -u b/core/vendor/composer/installed.json b/core/vendor/composer/installed.json
--- b/core/vendor/composer/installed.json
+++ b/core/vendor/composer/installed.json
@@ -3447,8 +3447,8 @@
     },
     {
         "name": "symfony/psr-http-message-bridge",
-        "version": "dev-master",
-        "version_normalized": "9999999-dev",
+        "version": "v0.1",
+        "version_normalized": "0.1.0.0",
         "source": {
             "type": "git",
             "url": "https://github.com/symfony/psr-http-message-bridge.git",
@@ -3503,8 +3503,8 @@
     },
     {
         "name": "zendframework/zend-diactoros",
-        "version": "dev-master",
-        "version_normalized": "9999999-dev",
+        "version": "1.0.1",
+        "version_normalized": "1.0.1.0",
         "source": {
             "type": "git",
             "url": "https://github.com/zendframework/zend-diactoros.git",