diff --git a/spacelift.info.yml b/spacelift.info.yml
index 0950eb2..18a6a7e 100644
--- a/spacelift.info.yml
+++ b/spacelift.info.yml
@@ -2,7 +2,7 @@ name: Spacelift
 type: theme
 base theme: classy
 description: A forward-thinking, developer-focused base theme for Drupal 8.
-core: 8.x
+core_version_requirement: ^8 || ^9
 regions:
   utility: Utility
   header: Header
diff --git a/spacelift.theme b/spacelift.theme
index bccac86..39ffb02 100644
--- a/spacelift.theme
+++ b/spacelift.theme
@@ -81,7 +81,7 @@ function spacelift_preprocess_block(&$variables) {
 
       $currentUrl = \Drupal\Core\Url::fromRouteMatch(\Drupal::routeMatch())->getInternalPath();
 
-      $parentPath = $alias = \Drupal::service('path.alias_manager')->getAliasByPath('/' . $parentUrl->getInternalPath());
+      $parentPath = $alias = \Drupal::service('path_alias.manager')->getAliasByPath('/' . $parentUrl->getInternalPath());
       $parentUrlActive = ($parentUrl->getInternalPath() == $currentUrl);
     }