diff --git a/core/config/schema/core.extension.schema.yml b/core/config/schema/core.extension.schema.yml
index 9565d8a..a78d462 100644
--- a/core/config/schema/core.extension.schema.yml
+++ b/core/config/schema/core.extension.schema.yml
@@ -28,5 +28,5 @@ core.extension:
             type: string
             label: 'Version at install time'
           schema:
-            type: string
+            type: integer
             label: 'Currently installed schema version'
diff --git a/core/modules/system/src/Tests/Update/UpdateScriptTest.php b/core/modules/system/src/Tests/Update/UpdateScriptTest.php
index cba80ca..81ae59a 100644
--- a/core/modules/system/src/Tests/Update/UpdateScriptTest.php
+++ b/core/modules/system/src/Tests/Update/UpdateScriptTest.php
@@ -182,11 +182,13 @@ function testSuccessfulUpdateFunctionality() {
     // Reset the static cache to ensure we have the most current setting.
     $schema_version = drupal_get_installed_schema_version('update_script_test', TRUE);
     $this->assertEqual($schema_version, 8001, 'update_script_test schema version is 8001 after updating.');
+    $this->assertIdentical(8001, $this->config('core.extension')->get('versions.update_script_test.schema'), 'update_script_test schema version is 8001 in core.extension config after updating.');
 
     // Set the installed schema version to one less than the current update.
     drupal_set_installed_schema_version('update_script_test', $schema_version - 1);
     $schema_version = drupal_get_installed_schema_version('update_script_test', TRUE);
     $this->assertEqual($schema_version, 8000, 'update_script_test schema version overridden to 8000.');
+    $this->assertIdentical(8000, $this->config('core.extension')->get('versions.update_script_test.schema'), 'update_script_test schema version is overridden to 8000 in core.extension config.');
 
     // Click through update.php with 'access administration pages' and
     // 'access site reports' permissions.