diff --git a/src/Horizon/RabbitMQQueue.php b/src/Horizon/RabbitMQQueue.php
index 894cc24b..e2ca400d 100644
--- a/src/Horizon/RabbitMQQueue.php
+++ b/src/Horizon/RabbitMQQueue.php
@@ -26,7 +26,7 @@ class RabbitMQQueue extends BaseRabbitMQQueue
      *
      * @throws AMQPProtocolChannelException
      */
-    public function readyNow(string $queue = null): int
+    public function readyNow(?string $queue = null): int
     {
         return $this->size($queue);
     }
diff --git a/src/Queue/RabbitMQQueue.php b/src/Queue/RabbitMQQueue.php
index 957620ef..fadedce5 100644
--- a/src/Queue/RabbitMQQueue.php
+++ b/src/Queue/RabbitMQQueue.php
@@ -204,7 +204,7 @@ protected function publishBatch($jobs, $data = '', $queue = null): void
     /**
      * @throws AMQPProtocolChannelException
      */
-    public function bulkRaw(string $payload, string $queue = null, array $options = []): int|string|null
+    public function bulkRaw(string $payload, ?string $queue = null, array $options = []): int|string|null
     {
         [$destination, $exchange, $exchangeType, $attempts] = $this->publishProperties($queue, $options);
 
@@ -397,7 +397,7 @@ public function deleteExchange(string $name, bool $unused = false): void
      *
      * @throws AMQPProtocolChannelException
      */
-    public function isQueueExists(string $name = null): bool
+    public function isQueueExists(?string $name = null): bool
     {
         $queueName = $this->getQueue($name);
 
@@ -484,7 +484,7 @@ public function bindQueue(string $queue, string $exchange, string $routingKey =
     /**
      * Purge the queue of messages.
      */
-    public function purge(string $queue = null): void
+    public function purge(?string $queue = null): void
     {
         // create a temporary channel, so the main channel will not be closed on exception
         $channel = $this->createChannel();
@@ -637,7 +637,7 @@ protected function getDelayQueueArguments(string $destination, int $ttl): array
     /**
      * Get the exchange name, or empty string; as default value.
      */
-    protected function getExchange(string $exchange = null): string
+    protected function getExchange(?string $exchange = null): string
     {
         return $exchange ?? $this->getConfig()->getExchange();
     }
@@ -654,7 +654,7 @@ protected function getRoutingKey(string $destination): string
     /**
      * Get the exchangeType, or AMQPExchangeType::DIRECT as default.
      */
-    protected function getExchangeType(string $type = null): string
+    protected function getExchangeType(?string $type = null): string
     {
         $constant = AMQPExchangeType::class.'::'.Str::upper($type ?: $this->getConfig()->getExchangeType());
 
@@ -664,7 +664,7 @@ protected function getExchangeType(string $type = null): string
     /**
      * Get the exchange for failed messages.
      */
-    protected function getFailedExchange(string $exchange = null): string
+    protected function getFailedExchange(?string $exchange = null): string
     {
         return $exchange ?? $this->getConfig()->getFailedExchange();
     }
@@ -699,7 +699,7 @@ protected function isQueueDeclared(string $name): bool
      *
      * @throws AMQPProtocolChannelException
      */
-    protected function declareDestination(string $destination, string $exchange = null, string $exchangeType = AMQPExchangeType::DIRECT): void
+    protected function declareDestination(string $destination, ?string $exchange = null, string $exchangeType = AMQPExchangeType::DIRECT): void
     {
         // When an exchange is provided and no exchange is present in RabbitMQ, create an exchange.
         if ($exchange && ! $this->isExchangeExists($exchange)) {
diff --git a/tests/TestCase.php b/tests/TestCase.php
index 7d50fa67..f1ffb8d4 100644
--- a/tests/TestCase.php
+++ b/tests/TestCase.php
@@ -50,7 +50,7 @@ protected function getEnvironmentSetUp($app): void
         ]);
     }
 
-    protected function connection(string $name = null): RabbitMQQueue
+    protected function connection(?string $name = null): RabbitMQQueue
     {
         return Queue::connection($name);
     }