diff --git a/src/Command/TelegramSendMessageCommand.php b/src/Command/TelegramSendMessageCommand.php
index 029df03..a40a885 100644
--- a/src/Command/TelegramSendMessageCommand.php
+++ b/src/Command/TelegramSendMessageCommand.php
@@ -21,7 +21,7 @@ class TelegramSendMessageCommand extends Command
         parent::__construct();
     }
 
-    protected function configure()
+    protected function configure(): void
     {
         $this
             ->addOption('chat-id', 'c', InputOption::VALUE_OPTIONAL, 'ID of the chat')
diff --git a/src/Command/TelegramWebhookCommand.php b/src/Command/TelegramWebhookCommand.php
index 544cabb..3a4e2bd 100644
--- a/src/Command/TelegramWebhookCommand.php
+++ b/src/Command/TelegramWebhookCommand.php
@@ -28,7 +28,7 @@ class TelegramWebhookCommand extends Command
         parent::__construct();
     }
 
-    protected function configure()
+    protected function configure(): void
     {
         $this
             ->addArgument('mode', InputArgument::REQUIRED, 'Command mode (set or delete)')
diff --git a/src/Command/UpdateSubscriptionsCommand.php b/src/Command/UpdateSubscriptionsCommand.php
index ca16971..27f08db 100644
--- a/src/Command/UpdateSubscriptionsCommand.php
+++ b/src/Command/UpdateSubscriptionsCommand.php
@@ -32,7 +32,7 @@ class UpdateSubscriptionsCommand extends Command
         parent::__construct();
     }
 
-    protected function configure()
+    protected function configure(): void
     {
         $this
             ->addOption(
diff --git a/src/Command/UpdateUsersPrivacyCommand.php b/src/Command/UpdateUsersPrivacyCommand.php
index a9acdee..039af0e 100644
--- a/src/Command/UpdateUsersPrivacyCommand.php
+++ b/src/Command/UpdateUsersPrivacyCommand.php
@@ -32,7 +32,7 @@ class UpdateUsersPrivacyCommand extends Command
         parent::__construct();
     }
 
-    protected function configure()
+    protected function configure(): void
     {
         $this
             ->addOption(