diff --git a/Command/AbstractCommand.php b/Command/AbstractCommand.php
index d077b07..e682c31 100644
--- a/Command/AbstractCommand.php
+++ b/Command/AbstractCommand.php
@@ -74,7 +74,7 @@ public function __construct(
      *
      * @return int
      */
-    protected function execute(InputInterface $input, OutputInterface $output)
+    protected function execute(InputInterface $input, OutputInterface $output): int
     {
         $this->input = $input;
         $this->output = $output;
diff --git a/Command/ExportCommand.php b/Command/ExportCommand.php
index d64f94b..347c95e 100644
--- a/Command/ExportCommand.php
+++ b/Command/ExportCommand.php
@@ -60,7 +60,7 @@ public function __construct(
      *
      * @return void
      */
-    protected function configure()
+    protected function configure(): void
     {
         $this->setName(self::COMMAND_NAME);
         $this->setDescription('Export settings from "core_config_data" into a file');
@@ -130,7 +130,7 @@ protected function configure()
     /**
      * @return int
      */
-    protected function execute(InputInterface $input, OutputInterface $output)
+    protected function execute(InputInterface $input, OutputInterface $output): int
     {
         parent::execute($input, $output);
         $this->writeSection('Start Export');
diff --git a/Command/ImportCommand.php b/Command/ImportCommand.php
index 4146919..e80e2b6 100644
--- a/Command/ImportCommand.php
+++ b/Command/ImportCommand.php
@@ -72,7 +72,7 @@ public function __construct(
      *
      * @return void
      */
-    protected function configure()
+    protected function configure(): void
     {
         $this->setName(self::COMMAND_NAME);
         $this->setDescription('Import "core_config_data" settings for an environment');
@@ -143,7 +143,7 @@ protected function configure()
      *
      * @return int
      */
-    protected function execute(InputInterface $input, OutputInterface $output)
+    protected function execute(InputInterface $input, OutputInterface $output): int
     {
         parent::execute($input, $output);