diff --git a/src/FeaturesManager.php b/src/FeaturesManager.php
index 44a5e44..8fdaee9 100644
--- a/src/FeaturesManager.php
+++ b/src/FeaturesManager.php
@@ -1147,10 +1147,10 @@ class FeaturesManager implements FeaturesManagerInterface {
             'type' => $config_type,
             'dependents' => array_keys($dependency_manager->getDependentEntities('config', $name)),
             // Default to the install directory.
-            'subdirectory' => $existing_config_by_directory[$name] ?? InstallStorage::CONFIG_INSTALL_DIRECTORY,
+            'subdirectory' => isset($existing_config_by_directory[$name]) ? $existing_config_by_directory[$name] : InstallStorage::CONFIG_INSTALL_DIRECTORY,
             'package' => '',
             'providerExcluded' => NULL,
-            'provider' => $existing_config[$name] ?? NULL,
+            'provider' => isset($existing_config[$name]) ? $existing_config[$name] : NULL,
             'packageExcluded' => [],
           ]));
         }