diff --git a/core/modules/system/system.install b/core/modules/system/system.install
index 25f03bc..51fcdb0 100644
--- a/core/modules/system/system.install
+++ b/core/modules/system/system.install
@@ -186,6 +186,7 @@ function system_requirements($phase) {
     ];
   }
 
+  $is_test_site = drupal_valid_test_ua() || getenv('DRUPAL_DEV_SITE_PATH');
   if (version_compare($phpversion, DRUPAL_MINIMUM_UPDATE_PHP) < 0) {
     $requirements['php']['description'] = t('Your PHP installation is too old. Drupal requires at least PHP %version.', ['%version' => DRUPAL_MINIMUM_UPDATE_PHP]);
     $requirements['php']['severity'] = REQUIREMENT_ERROR;
@@ -193,17 +194,17 @@ function system_requirements($phase) {
   }
   if (version_compare($phpversion, DRUPAL_MINIMUM_PHP) < 0) {
     // Allow test installations of Drupal on the minimum update PHP.
-    $is_test_site = drupal_valid_test_ua() || getenv('DRUPAL_DEV_SITE_PATH');
     if ($phase === 'update') {
       $requirements['php']['description'] = t('Your PHP installation is too old. Drupal requires at least PHP %version.', ['%version' => DRUPAL_MINIMUM_PHP]);
       $requirements['php']['severity'] = REQUIREMENT_WARNING;
+      return $requirements;
     }
     elseif (!$is_test_site) {
       $requirements['php']['description'] = t('Your PHP installation is too old. Drupal requires at least PHP %version.', ['%version' => DRUPAL_MINIMUM_PHP]);
       $requirements['php']['severity'] = REQUIREMENT_ERROR;
+      // If PHP is old, it's not safe to continue with the requirements check.
+      return $requirements;
     }
-    // If PHP is old, it's not safe to continue with the requirements check.
-    return $requirements;
   }
   if (version_compare($phpversion, DRUPAL_RECOMMENDED_PHP) < 0) {
     if ($phase === 'runtime') {