diff --git a/src/Composer/Platform/Runtime.php b/src/Composer/Platform/Runtime.php
index 725c3dbbcfce..c59e9d060640 100644
--- a/src/Composer/Platform/Runtime.php
+++ b/src/Composer/Platform/Runtime.php
@@ -98,7 +98,12 @@ public function getExtensions(): array
      */
     public function getExtensionVersion(string $extension): string
     {
-        return phpversion($extension);
+        $version = phpversion($extension);
+        if ($version === false) {
+            $version = '0';
+        }
+
+        return $version;
     }
 
     /**
diff --git a/src/Composer/Repository/PlatformRepository.php b/src/Composer/Repository/PlatformRepository.php
index d31e0ede26f6..6cac92bec4a8 100644
--- a/src/Composer/Repository/PlatformRepository.php
+++ b/src/Composer/Repository/PlatformRepository.php
@@ -618,13 +618,8 @@ private function addDisabledPackage(CompletePackage $package): void
 
     /**
      * Parses the version and adds a new package to the repository
-     *
-     * @param string      $name
-     * @param null|string $prettyVersion
-     *
-     * @return void
      */
-    private function addExtension(string $name, ?string $prettyVersion): void
+    private function addExtension(string $name, string $prettyVersion): void
     {
         $extraDescription = null;