diff --git a/core/lib/Drupal/Core/Composer/Composer.php b/core/lib/Drupal/Core/Composer/Composer.php
index cae91964500..4119089a66a 100644
--- a/core/lib/Drupal/Core/Composer/Composer.php
+++ b/core/lib/Drupal/Core/Composer/Composer.php
@@ -101,7 +101,8 @@ class Composer {
    * Throw an exception if Composer is too old.
    */
   public static function ensureComposerVersion() {
-    $composerVersion = ComposerApp::getVersion();
+    $composerVersion = method_exists(ComposerApp::class, 'getVersion') ?
+      ComposerApp::getVersion() : ComposerApp::VERSION;
     if (Comparator::lessThan($composerVersion, '1.9.0')) {
       throw new \RuntimeException("Drupal core development requires Composer 1.9.0, but Composer $composerVersion is installed. Please run 'composer self-update'.");
     }