diff --git a/composer.lock b/composer.lock
index cc888bf28245d40a85c7d3c07292046ad14b5aee..99ea68c4e0cb4b511a74a9b33b60578db2b8ecb8 100644
--- a/composer.lock
+++ b/composer.lock
@@ -451,7 +451,7 @@
         },
         {
             "name": "drupal/core",
-            "version": "9.0.0-alpha1",
+            "version": "9.0.x-dev",
             "dist": {
                 "type": "path",
                 "url": "core",
@@ -682,11 +682,11 @@
         },
         {
             "name": "drupal/core-project-message",
-            "version": "9.0.0-alpha1",
+            "version": "9.0.x-dev",
             "dist": {
                 "type": "path",
                 "url": "composer/Plugin/ProjectMessage",
-                "reference": "0691ca6beba657e6da57a893b1c6da757d16afc8"
+                "reference": "3b795f469441eb27854798f70cb38e717d80bbfc"
             },
             "require": {
                 "composer-plugin-api": "^1.1",
@@ -712,7 +712,7 @@
         },
         {
             "name": "drupal/core-vendor-hardening",
-            "version": "9.0.0-alpha1",
+            "version": "9.0.x-dev",
             "dist": {
                 "type": "path",
                 "url": "composer/Plugin/VendorHardening",
@@ -4099,6 +4099,9 @@
                 "ext-zip": "Enabling the zip extension allows you to unzip archives",
                 "ext-zlib": "Allow gzip compression of HTTP requests"
             },
+            "bin": [
+                "bin/composer"
+            ],
             "type": "library",
             "extra": {
                 "branch-alias": {
@@ -6525,6 +6528,9 @@
     "aliases": [],
     "minimum-stability": "dev",
     "stability-flags": {
+        "drupal/core": 20,
+        "drupal/core-project-message": 20,
+        "drupal/core-vendor-hardening": 20,
         "behat/mink": 20,
         "behat/mink-selenium2-driver": 20
     },
diff --git a/composer/Metapackage/CoreRecommended/composer.json b/composer/Metapackage/CoreRecommended/composer.json
index e63ce508e85c47fca5b584f8ede3baf7ee078e1c..edfedd451cf692727188134caaf890a20d37ec28 100644
--- a/composer/Metapackage/CoreRecommended/composer.json
+++ b/composer/Metapackage/CoreRecommended/composer.json
@@ -7,7 +7,7 @@
         "webflo/drupal-core-strict": "*"
     },
     "require": {
-        "drupal/core": "9.0.0-alpha1",
+        "drupal/core": "9.0.x-dev",
         "asm89/stack-cors": "1.3.0",
         "composer/installers": "v1.7.0",
         "composer/semver": "1.5.1",
diff --git a/composer/Metapackage/PinnedDevDependencies/composer.json b/composer/Metapackage/PinnedDevDependencies/composer.json
index 57168fb5a7b86d3892ce4fe45505822a6a6c1fc1..8eeed3b8806b42d7468d6589049b659995185a20 100644
--- a/composer/Metapackage/PinnedDevDependencies/composer.json
+++ b/composer/Metapackage/PinnedDevDependencies/composer.json
@@ -7,7 +7,7 @@
         "webflo/drupal-core-require-dev": "*"
     },
     "require": {
-        "drupal/core": "9.0.0-alpha1",
+        "drupal/core": "9.0.x-dev",
         "behat/mink": "1.8.0 | 1.7.1.1 | 1.7.x-dev",
         "behat/mink-browserkit-driver": "1.3.3",
         "behat/mink-goutte-driver": "v1.2.1",
diff --git a/core/lib/Drupal.php b/core/lib/Drupal.php
index 3844b8cfe491f0b0a4ea891db9e6ffbb9166d5c3..fc598803aef359971542fe7cae28cb07ff2a6ff4 100644
--- a/core/lib/Drupal.php
+++ b/core/lib/Drupal.php
@@ -81,7 +81,7 @@ class Drupal {
   /**
    * The current system version.
    */
-  const VERSION = '9.0.0-alpha1';
+  const VERSION = '9.0.0-dev';
 
   /**
    * Core API compatibility.