diff --git a/extensions/package-manager/src/Api/Controller/ConfigureComposerController.php b/extensions/package-manager/src/Api/Controller/ConfigureComposerController.php
index 54504cd2b3..b065d2cbc2 100755
--- a/extensions/package-manager/src/Api/Controller/ConfigureComposerController.php
+++ b/extensions/package-manager/src/Api/Controller/ConfigureComposerController.php
@@ -95,6 +95,9 @@ protected function composerConfig(ServerRequestInterface $request): array
                 Arr::set($composerJson, $key, $value);
             }
 
+            // Always prefer stable releases.
+            $composerJson['prefer-stable'] = true;
+
             $this->composerJson->set($composerJson);
         }