diff --git a/src/Plugin/Alter/LibraryInfo.php b/src/Plugin/Alter/LibraryInfo.php
index 4a1999a..92055b1 100644
--- a/src/Plugin/Alter/LibraryInfo.php
+++ b/src/Plugin/Alter/LibraryInfo.php
@@ -27,21 +27,23 @@ class LibraryInfo extends PluginBase implements AlterInterface {
       if ($assets = $provider->getAssets()) {
         $libraries['base-theme'] = NestedArray::mergeDeepArray([$assets, $libraries['base-theme']], TRUE);
 
-        // Add a specific version and theme CSS overrides file.
+        // Add a specific version and theme CSS overrides file if cdn is enabled.
         // @todo This should be retrieved by the Provider API.
-        $version = $this->theme->getSetting('cdn_' . $provider->getPluginId() . '_version') ?: Bootstrap::FRAMEWORK_VERSION;
-        $libraries['base-theme']['version'] = $version;
-        $provider_theme = $this->theme->getSetting('cdn_' . $provider->getPluginId() . '_theme') ?: 'bootstrap';
-        $provider_theme = $provider_theme === 'bootstrap' || $provider_theme === 'bootstrap_theme' ? '' : "-$provider_theme";
+        $version = $this->theme->getSetting('cdn_' . $provider->getPluginId() . '_version');
+        if ($version) {
+          $libraries['base-theme']['version'] = $version;
+          $provider_theme = $this->theme->getSetting('cdn_' . $provider->getPluginId() . '_theme') ?: 'bootstrap';
+          $provider_theme = $provider_theme === 'bootstrap' || $provider_theme === 'bootstrap_theme' ? '' : "-$provider_theme";
 
-        foreach ($this->theme->getAncestry(TRUE) as $ancestor) {
-          $overrides = $ancestor->getPath() . "/css/$version/overrides$provider_theme.min.css";
-          if (file_exists($overrides)) {
-            // Since this uses a relative path to the ancestor from DRUPAL_ROOT,
-            // we must prefix the entire path with / so it doesn't append the
-            // active theme's path (which would duplicate the prefix).
-            $libraries['base-theme']['css']['theme']["/$overrides"] = [];
-            break;
+          foreach ($this->theme->getAncestry(TRUE) as $ancestor) {
+            $overrides = $ancestor->getPath() . "/css/$version/overrides$provider_theme.min.css";
+            if (file_exists($overrides)) {
+              // Since this uses a relative path to the ancestor from DRUPAL_ROOT,
+              // we must prefix the entire path with / so it doesn't append the
+              // active theme's path (which would duplicate the prefix).
+              $libraries['base-theme']['css']['theme']["/$overrides"] = [];
+              break;
+            }
           }
         }
       }