diff --git a/DependencyInjection/DoctrineMigrations/AbstractDoctrineMigrationsLoader.php b/DependencyInjection/DoctrineMigrations/AbstractDoctrineMigrationsLoader.php
index 6ce549ec..455ea12b 100644
--- a/DependencyInjection/DoctrineMigrations/AbstractDoctrineMigrationsLoader.php
+++ b/DependencyInjection/DoctrineMigrations/AbstractDoctrineMigrationsLoader.php
@@ -22,6 +22,6 @@ abstract public function createMigrationConfigurationService(
         ContainerBuilder $container,
         string $connectionName,
         string $serviceId,
-        string $filename = null
+        ?string $filename = null
     ): void;
 }
diff --git a/DependencyInjection/DoctrineMigrations/V2MigrationsLoader.php b/DependencyInjection/DoctrineMigrations/V2MigrationsLoader.php
index 1cfc8e0c..841dce9f 100644
--- a/DependencyInjection/DoctrineMigrations/V2MigrationsLoader.php
+++ b/DependencyInjection/DoctrineMigrations/V2MigrationsLoader.php
@@ -52,7 +52,7 @@ public function createMigrationConfigurationService(
         ContainerBuilder $container,
         string $connectionName,
         string $serviceId,
-        string $filename = null
+        ?string $filename = null
     ): void {
         if (!$container->has(Configuration::class)) {
             $container->register(Configuration::class)
diff --git a/DependencyInjection/DoctrineMigrations/V3MigrationsLoader.php b/DependencyInjection/DoctrineMigrations/V3MigrationsLoader.php
index 6ed63a39..bfe29a43 100644
--- a/DependencyInjection/DoctrineMigrations/V3MigrationsLoader.php
+++ b/DependencyInjection/DoctrineMigrations/V3MigrationsLoader.php
@@ -23,7 +23,7 @@ public function createMigrationConfigurationService(
         ContainerBuilder $container,
         string $connectionName,
         string $serviceId,
-        string $filename = null
+        ?string $filename = null
     ): void {
         if (null !== $filename) {
             $configurationClass = $this->getConfigurationLoaderClass($container, $filename);
diff --git a/Helper/ConsoleReporter.php b/Helper/ConsoleReporter.php
index 0748c16d..7c9a6579 100644
--- a/Helper/ConsoleReporter.php
+++ b/Helper/ConsoleReporter.php
@@ -22,7 +22,7 @@ class ConsoleReporter implements ReporterInterface
      */
     protected $output;
 
-    public function __construct(OutputInterface $output = null)
+    public function __construct(?OutputInterface $output = null)
     {
         if (null === $output) {
             $output = new ConsoleOutput();
diff --git a/Helper/RawConsoleReporter.php b/Helper/RawConsoleReporter.php
index f496b0d9..181f35ee 100644
--- a/Helper/RawConsoleReporter.php
+++ b/Helper/RawConsoleReporter.php
@@ -22,7 +22,7 @@ class RawConsoleReporter implements ReporterInterface
      */
     protected $output;
 
-    public function __construct(OutputInterface $output = null)
+    public function __construct(?OutputInterface $output = null)
     {
         if (null === $output) {
             $output = new ConsoleOutput();