diff --git a/core/includes/update.inc b/core/includes/update.inc
index f956605..c628d3f 100644
--- a/core/includes/update.inc
+++ b/core/includes/update.inc
@@ -100,34 +100,31 @@ function update_settings_file_requirements() {
 }
 
 /**
- * Checks whether the minimum system schema version has been satisfied.
- *
- * Upgrading from a 7.x site database should block the update process.
- * Ensure that the site is running Drupal 8 before proceeding. Not that this
- * has to happen AFTER the database bootstraps because of
- * drupal_get_installed_schema_version().
+ * Returns whether the minimum schema requirement has been satisfied.
  *
  * @return array
  *  A requirements info array.
  */
-function update_migrate_requirements() {
+function update_system_schema_requirements() {
   $requirements = array();
-  try {
-    $system_schema = drupal_get_installed_schema_version('system');
-  }
-  catch (\Exception $e) {
-    $system_schema = db_query('SELECT schema_version FROM {system} WHERE name = :system', array(':system' => 'system'))->fetchField();
+
+  $system_schema = drupal_get_installed_schema_version('system');
+
+  $requirements['minimum schema']['title'] = 'Minimum schema version';
+  if ($system_schema >= \Drupal::CORE_MINIMUM_SCHEMA_VERSION) {
+    $requirements['minimum schema'] += array(
+      'value' => 'The installed schema version meets the minimum.',
+      'description' => 'Schema version: ' . $system_schema,
+    );
   }
-  if ($system_schema < \Drupal::CORE_MINIMUM_SCHEMA_VERSION) {
-    $requirements = array(
-      'drupal 7 version' => array(
-        'title' => 'Drupal 7 version',
-        'value' => 'Your site database is from a Drupal 7 or earlier site.',
-        'severity' => REQUIREMENT_ERROR,
-        'description' => 'Migrate your Drupal 7 installation to a Drupal 8 installation using the Migrate module. Updating directly from Drupal 7 to Drupal 8 is not supported.',
-      ),
+  else {
+    $requirements['minimum schema'] += array(
+      'value' => 'The installed schema version does not meet the minimum.',
+      'severity' => REQUIREMENT_ERROR,
+      'description' => 'Your system schema version is ' . $system_schema . '. Updating directly from a schema version prior to 8000 is not supported. You must <a href="https://drupal.org/node/2179269">migrate your site to Drupal 8</a> first.',
     );
   }
+
   return $requirements;
 }
 
@@ -140,15 +137,10 @@ function update_migrate_requirements() {
  *   FALSE.
  */
 function update_check_requirements($skip_warnings = FALSE) {
-  // Upgrading from a 7.x site database should block the update process.
-  $requirements = update_migrate_requirements();
-  // If the user is not upgrading for a system schema prior to 8.x, gather
-  // any additional extra requirements.
-  if (empty($requirements)) {
-    // Check requirements of all loaded modules.
-    $requirements = \Drupal::moduleHandler()->invokeAll('requirements', array('update'));
-    $requirements += update_settings_file_requirements();
-  }
+  // Check requirements of all loaded modules.
+  $requirements = \Drupal::moduleHandler()->invokeAll('requirements', array('update'));
+  $requirements += update_system_schema_requirements();
+  $requirements += update_settings_file_requirements();
   $severity = drupal_requirements_severity($requirements);
 
   // If there are errors, always display them. If there are only warnings, skip
@@ -189,6 +181,25 @@ function update_prepare_d8_bootstrap() {
   // Bootstrap to configuration.
   drupal_bootstrap(DRUPAL_BOOTSTRAP_CONFIGURATION);
 
+  // Bootstrap the database.
+  require_once __DIR__ . '/database.inc';
+
+  // Updating from a site schema version prior to 8000 should block the update
+  // process. Ensure that the site is not attempting to update a database
+  // created in a previous version of Drupal.
+  try {
+    $system_schema = db_query('SELECT schema_version FROM {system} WHERE name = :system', array(':system' => 'system'))->fetchField();
+  }
+  catch (\Exception $e) {
+    // The schema_version does not exist in the system table, so continue
+    // for the moment assuming that this is a Drupal 8 database schema. Another
+    // check will be made later to verify this is the case.
+  }
+  if (isset($system_schema) && $system_schema < \Drupal::CORE_MINIMUM_SCHEMA_VERSION) {
+    print 'Your system schema version is ' . $system_schema . '. Updating directly from a schema version prior to 8000 is not supported. You must <a href="https://drupal.org/node/2179269">migrate your site to Drupal 8</a> first.';
+    exit;
+  }
+
   // During the bootstrap to DRUPAL_BOOTSTRAP_PAGE_CACHE, code will try to read
   // the cache but the cache tables are not compatible yet. Use the Null backend
   // by default to avoid exceptions.
@@ -213,9 +224,6 @@ function update_prepare_d8_bootstrap() {
   $kernel = new DrupalKernel('update', drupal_classloader(), FALSE);
   $kernel->boot();
 
-  // Bootstrap the database.
-  require_once __DIR__ . '/database.inc';
-
   // module.inc is not yet loaded but there are calls to module_config_sort()
   // below.
   require_once __DIR__ . '/module.inc';
diff --git a/core/modules/system/lib/Drupal/system/Tests/Update/UpdateScriptTest.php b/core/modules/system/lib/Drupal/system/Tests/Update/UpdateScriptTest.php
index 4158cea..ef2f136 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Update/UpdateScriptTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Update/UpdateScriptTest.php
@@ -41,6 +41,28 @@ function setUp() {
   }
 
   /**
+   * Tests that updates from schema versions prior to 8000 are prevented.
+   */
+  function testInvalidMigration() {
+    // Mock a D7 system table so that the schema value of the system module
+    // can be retrieved.
+    db_create_table('system', $this->getSystemSchema());
+    // Assert that the table exists.
+    $this->assertTrue(db_table_exists('system'), 'The table exists.');
+    // Insert a value for the system module.
+    db_insert('system')
+      ->fields(array(
+        'name' => 'system',
+        'schema_version' => 7000,
+      ))
+      ->execute();
+    $system_schema = db_query('SELECT schema_version FROM {system} WHERE name = :system', array(':system' => 'system'))->fetchField();
+    $this->drupalGet($this->update_url, array('external' => TRUE));
+    $text = 'Your system schema version is ' . $system_schema . '. Updating directly from a schema version prior to 8000 is not supported. You must <a href="https://drupal.org/node/2179269">migrate your site to Drupal 8</a> first.';
+    $this->assertRaw($text, 'Updates from schema versions prior to 8000 are prevented.');
+  }
+
+  /**
    * Tests access to the update script.
    */
   function testUpdateAccess() {
@@ -218,4 +240,78 @@ function testSuccessfulUpdateFunctionality() {
     $this->clickLink('Administration pages');
     $this->assertResponse(200);
   }
+
+  /**
+   * Returns the Drupal 7 system table schema.
+   */
+  public function getSystemSchema() {
+    return array(
+      'description' => "A list of all modules, themes, and theme engines that are or have been installed in Drupal's file system.",
+      'fields' => array(
+        'filename' => array(
+          'description' => 'The path of the primary file for this item, relative to the Drupal root; e.g. modules/node/node.module.',
+          'type' => 'varchar',
+          'length' => 255,
+          'not null' => TRUE,
+          'default' => '',
+        ),
+        'name' => array(
+          'description' => 'The name of the item; e.g. node.',
+          'type' => 'varchar',
+          'length' => 255,
+          'not null' => TRUE,
+          'default' => '',
+        ),
+        'type' => array(
+          'description' => 'The type of the item, either module, theme, or theme_engine.',
+          'type' => 'varchar',
+          'length' => 12,
+          'not null' => TRUE,
+          'default' => '',
+        ),
+        'owner' => array(
+          'description' => "A theme's 'parent' . Can be either a theme or an engine.",
+          'type' => 'varchar',
+          'length' => 255,
+          'not null' => TRUE,
+          'default' => '',
+        ),
+        'status' => array(
+          'description' => 'Boolean indicating whether or not this item is enabled.',
+          'type' => 'int',
+          'not null' => TRUE,
+          'default' => 0,
+        ),
+        'bootstrap' => array(
+          'description' => "Boolean indicating whether this module is loaded during Drupal's early bootstrapping phase (e.g. even before the page cache is consulted).",
+          'type' => 'int',
+          'not null' => TRUE,
+          'default' => 0,
+        ),
+        'schema_version' => array(
+          'description' => "The module's database schema version number. -1 if the module is not installed (its tables do not exist); 0 or the largest N of the module's hook_update_N() function that has either been run or existed when the module was first installed.",
+          'type' => 'int',
+          'not null' => TRUE,
+          'default' => -1,
+          'size' => 'small',
+        ),
+        'weight' => array(
+          'description' => "The order in which this module's hooks should be invoked relative to other modules. Equal-weighted modules are ordered by name.",
+          'type' => 'int',
+          'not null' => TRUE,
+          'default' => 0,
+        ),
+        'info' => array(
+          'description' => "A serialized array containing information from the module's .info file; keys can include name, description, package, version, core, dependencies, and php.",
+          'type' => 'blob',
+          'not null' => FALSE,
+        ),
+      ),
+      'primary key' => array('filename'),
+      'indexes' => array(
+        'system_list' => array('status', 'bootstrap', 'type', 'weight', 'name'),
+        'type_name' => array('type', 'name'),
+      ),
+    );
+  }
 }