diff --git a/src/Propel/Generator/Command/MigrationUpCommand.php b/src/Propel/Generator/Command/MigrationUpCommand.php
index cc79558bd..daea8a44e 100644
--- a/src/Propel/Generator/Command/MigrationUpCommand.php
+++ b/src/Propel/Generator/Command/MigrationUpCommand.php
@@ -44,7 +44,7 @@ protected function configure()
      *
      * @throws \Propel\Runtime\Exception\RuntimeException
      */
-    protected function execute(InputInterface $input, OutputInterface $output)
+    protected function execute(InputInterface $input, OutputInterface $output): int
     {
         $configOptions = [];