diff --git a/core/lib/Drupal.php b/core/lib/Drupal.php
index 04fac02..e836531 100644
--- a/core/lib/Drupal.php
+++ b/core/lib/Drupal.php
@@ -77,6 +77,16 @@
 class Drupal {
 
   /**
+   * The current system version.
+   */
+  const VERSION = '8.0-dev';
+
+  /**
+   * Core API compatibility.
+   */
+  const CORE_COMPATIBILITY = '8.x';
+
+  /**
    * The currently active container object.
    *
    * @var \Symfony\Component\DependencyInjection\ContainerInterface
diff --git a/core/lib/Drupal/Core/Extension/ModuleHandler.php b/core/lib/Drupal/Core/Extension/ModuleHandler.php
index b9e5724..3ac1d89 100644
--- a/core/lib/Drupal/Core/Extension/ModuleHandler.php
+++ b/core/lib/Drupal/Core/Extension/ModuleHandler.php
@@ -464,7 +464,7 @@ protected function parseDependency($dependency) {
     // supports. Also, op is optional and defaults to equals.
     $p_op = '(?<operation>!=|==|=|<|<=|>|>=|<>)?';
     // Core version is always optional: 8.x-2.x and 2.x is treated the same.
-    $p_core = '(?:' . preg_quote(DRUPAL_CORE_COMPATIBILITY) . '-)?';
+    $p_core = '(?:' . preg_quote(\Drupal::CORE_COMPATIBILITY) . '-)?';
     $p_major = '(?<major>\d+)';
     // By setting the minor version to x, branches can be matched.
     $p_minor = '(?<minor>(?:\d+|x)(?:-[A-Za-z]+\d+)?)';
diff --git a/core/lib/Drupal/Core/SystemListingInfo.php b/core/lib/Drupal/Core/SystemListingInfo.php
index 3c34a5e..714365b 100644
--- a/core/lib/Drupal/Core/SystemListingInfo.php
+++ b/core/lib/Drupal/Core/SystemListingInfo.php
@@ -61,7 +61,7 @@ protected function process(array $files, array $files_to_add) {
         // If the module or theme is incompatible with Drupal core, remove it
         // from the array for the current search directory, so it is not
         // overwritten when merged with the $files array.
-        if (isset($info['core']) && $info['core'] != DRUPAL_CORE_COMPATIBILITY) {
+        if (isset($info['core']) && $info['core'] != \Drupal::CORE_COMPATIBILITY) {
           unset($files_to_add[$file_key]);
         }
       }
diff --git a/core/modules/system/lib/Drupal/system/Form/ModulesListForm.php b/core/modules/system/lib/Drupal/system/Form/ModulesListForm.php
index 32d8db7..ffe1253 100644
--- a/core/modules/system/lib/Drupal/system/Form/ModulesListForm.php
+++ b/core/modules/system/lib/Drupal/system/Form/ModulesListForm.php
@@ -222,10 +222,10 @@ protected function buildRow(array $modules, $module, $distribution) {
     $status = '';
 
     // Check the core compatibility.
-    if ($module->info['core'] != DRUPAL_CORE_COMPATIBILITY) {
+    if ($module->info['core'] != \Drupal::CORE_COMPATIBILITY) {
       $compatible = FALSE;
       $status .= $this->t('This version is not compatible with Drupal !core_version and should be replaced.', array(
-        '!core_version' => DRUPAL_CORE_COMPATIBILITY,
+        '!core_version' => \Drupal::CORE_COMPATIBILITY,
       ));
     }
 
@@ -259,7 +259,7 @@ protected function buildRow(array $modules, $module, $distribution) {
         $name = $modules[$dependency]->info['name'];
         // Disable the module's checkbox if it is incompatible with the
         // dependency's version.
-        if ($incompatible_version = drupal_check_incompatibility($version, str_replace(DRUPAL_CORE_COMPATIBILITY . '-', '', $modules[$dependency]->info['version']))) {
+        if ($incompatible_version = drupal_check_incompatibility($version, str_replace(\Drupal::CORE_COMPATIBILITY . '-', '', $modules[$dependency]->info['version']))) {
           $row['#requires'][$dependency] = $this->t('@module (<span class="admin-missing">incompatible with</span> version @version)', array(
             '@module' => $name . $incompatible_version,
             '@version' => $modules[$dependency]->info['version'],
@@ -268,7 +268,7 @@ protected function buildRow(array $modules, $module, $distribution) {
         }
         // Disable the checkbox if the dependency is incompatible with this
         // version of Drupal core.
-        elseif ($modules[$dependency]->info['core'] != DRUPAL_CORE_COMPATIBILITY) {
+        elseif ($modules[$dependency]->info['core'] != \Drupal::CORE_COMPATIBILITY) {
           $row['#requires'][$dependency] = $this->t('@module (<span class="admin-missing">incompatible with</span> this version of Drupal core)', array(
             '@module' => $name,
           ));
diff --git a/core/modules/update/lib/Drupal/update/Tests/UpdateCoreUnitTest.php b/core/modules/update/lib/Drupal/update/Tests/UpdateCoreUnitTest.php
index ac26bd7..c682f99 100644
--- a/core/modules/update/lib/Drupal/update/Tests/UpdateCoreUnitTest.php
+++ b/core/modules/update/lib/Drupal/update/Tests/UpdateCoreUnitTest.php
@@ -45,20 +45,20 @@ function testUpdateBuildFetchUrl() {
     $project['info']['project status url'] = 'http://www.example.com';
     $project['includes'] = array('module1' => 'Module 1', 'module2' => 'Module 2');
     $site_key = '';
-    $expected = 'http://www.example.com/' . $project['name'] . '/' . DRUPAL_CORE_COMPATIBILITY;
+    $expected = 'http://www.example.com/' . $project['name'] . '/' . \Drupal::CORE_COMPATIBILITY;
     $url = _update_build_fetch_url($project, $site_key);
     $this->assertEqual($url, $expected, "'$url' when no site_key provided should be '$expected'.");
 
     //For disabled projects it shouldn't add the site key either.
     $site_key = 'site_key';
     $project['project_type'] = 'disabled';
-    $expected = 'http://www.example.com/' . $project['name'] . '/' . DRUPAL_CORE_COMPATIBILITY;
+    $expected = 'http://www.example.com/' . $project['name'] . '/' . \Drupal::CORE_COMPATIBILITY;
     $url = _update_build_fetch_url($project, $site_key);
     $this->assertEqual($url, $expected, "'$url' should be '$expected' for disabled projects.");
 
     //for enabled projects, adding the site key
     $project['project_type'] = '';
-    $expected = 'http://www.example.com/' . $project['name'] . '/' . DRUPAL_CORE_COMPATIBILITY;
+    $expected = 'http://www.example.com/' . $project['name'] . '/' . \Drupal::CORE_COMPATIBILITY;
     $expected .= '?site_key=site_key';
     $expected .= '&list=' . rawurlencode('module1,module2');
     $url = _update_build_fetch_url($project, $site_key);
@@ -67,7 +67,7 @@ function testUpdateBuildFetchUrl() {
     // http://drupal.org/node/1481156 test incorrect logic when URL contains
     // a question mark.
     $project['info']['project status url'] = 'http://www.example.com/?project=';
-    $expected = 'http://www.example.com/?project=/' . $project['name'] . '/' . DRUPAL_CORE_COMPATIBILITY;
+    $expected = 'http://www.example.com/?project=/' . $project['name'] . '/' . \Drupal::CORE_COMPATIBILITY;
     $expected .= '&site_key=site_key';
     $expected .= '&list=' . rawurlencode('module1,module2');
     $url = _update_build_fetch_url($project, $site_key);
diff --git a/core/modules/views/lib/Drupal/views/Entity/View.php b/core/modules/views/lib/Drupal/views/Entity/View.php
index e98ae01..82f93c4 100644
--- a/core/modules/views/lib/Drupal/views/Entity/View.php
+++ b/core/modules/views/lib/Drupal/views/Entity/View.php
@@ -79,7 +79,7 @@ class View extends ConfigEntityBase implements ViewStorageInterface {
    *
    * @var int
    */
-  protected $core = DRUPAL_CORE_COMPATIBILITY;
+  protected $core = \Drupal::CORE_COMPATIBILITY;
 
   /**
    * Stores all display handlers of this view.
diff --git a/core/modules/views/tests/Drupal/views/Tests/Plugin/Block/ViewsBlockTest.php b/core/modules/views/tests/Drupal/views/Tests/Plugin/Block/ViewsBlockTest.php
index 94a2cf7..e94586f 100644
--- a/core/modules/views/tests/Drupal/views/Tests/Plugin/Block/ViewsBlockTest.php
+++ b/core/modules/views/tests/Drupal/views/Tests/Plugin/Block/ViewsBlockTest.php
@@ -12,9 +12,6 @@
 use Drupal\block\Plugin\views\display\Block;
 
 // @todo Remove this once the constant got converted.
-if (!defined('DRUPAL_CORE_COMPATIBILITY')) {
-  define('DRUPAL_CORE_COMPATIBILITY', '8.x');
-}
 if (!defined('BLOCK_LABEL_VISIBLE')) {
   define('BLOCK_LABEL_VISIBLE', 'visible');
 }
diff --git a/core/modules/views_ui/tests/Drupal/views_ui/Tests/ViewUIObjectTest.php b/core/modules/views_ui/tests/Drupal/views_ui/Tests/ViewUIObjectTest.php
index 9b52116..172d6ef 100644
--- a/core/modules/views_ui/tests/Drupal/views_ui/Tests/ViewUIObjectTest.php
+++ b/core/modules/views_ui/tests/Drupal/views_ui/Tests/ViewUIObjectTest.php
@@ -13,10 +13,6 @@
 use Drupal\views_ui\ViewUI;
 use Symfony\Component\DependencyInjection\Container;
 
-if (!defined('DRUPAL_CORE_COMPATIBILITY')) {
-  define('DRUPAL_CORE_COMPATIBILITY', '8.x');
-}
-
 /**
  * Tests the ViewUI class.
  *