diff --git a/composer.json b/composer.json
index ab45c1e..34c2f3c 100644
--- a/composer.json
+++ b/composer.json
@@ -23,7 +23,7 @@
     "require-dev": {
         "phpunit/phpunit": "^9",
         "flyeralarm/php-code-validator": "^3.2",
-        "vimeo/psalm": "^3.4"
+        "vimeo/psalm": "^4.6"
     },
     "autoload": {
         "psr-4": {
diff --git a/psalm.xml b/psalm.xml
index 42f355b..7da42dd 100644
--- a/psalm.xml
+++ b/psalm.xml
@@ -34,7 +34,6 @@
         <MissingReturnType errorLevel="info" />
         <MissingPropertyType errorLevel="info" />
         <InvalidDocblock errorLevel="info" />
-        <MisplacedRequiredParam errorLevel="info" />
 
         <PropertyNotSetInConstructor errorLevel="info" />
         <MissingConstructor errorLevel="info" />
diff --git a/src/Client.php b/src/Client.php
index 67748d8..c77cdcd 100644
--- a/src/Client.php
+++ b/src/Client.php
@@ -296,7 +296,7 @@ private function send(string $key, $value, string $type, float $sampleRate, arra
      */
     public function setNamespace(string $namespace): void
     {
-        $this->namespace = (string) $namespace;
+        $this->namespace = $namespace;
     }
 
     /**
diff --git a/src/Connection/File.php b/src/Connection/File.php
index 51d6b87..70d67d3 100644
--- a/src/Connection/File.php
+++ b/src/Connection/File.php
@@ -9,7 +9,8 @@
 class File implements Connection
 {
     /**
-     * @var null|resource|closed-resource
+     * @psalm-suppress PossiblyInvalidArgument
+     * @var null|resource
      */
     private $handle;
 
@@ -60,6 +61,7 @@ public function sendMessages(array $messages): void
     public function close(): void
     {
         if (is_resource($this->handle)) {
+            /** @psalm-suppress InvalidPropertyAssignmentValue */
             fclose($this->handle);
         }
 
diff --git a/src/Connection/InetSocket.php b/src/Connection/InetSocket.php
index 2206417..e2a7946 100644
--- a/src/Connection/InetSocket.php
+++ b/src/Connection/InetSocket.php
@@ -64,7 +64,7 @@ public function __construct(
         $this->host = $host;
         $this->port = $port;
         $this->persistent = $persistent;
-        $this->maxPayloadSize = (int) $mtu -
+        $this->maxPayloadSize = $mtu -
             self::IP_HEADER_SIZE -
             $this->getProtocolHeaderSize() -
             strlen(self::LINE_DELIMITER);
@@ -144,7 +144,9 @@ private function cutIntoMtuSizedPackets(array $messages): array
         if ($this->allowFragmentation()) {
             $message = join(self::LINE_DELIMITER, $messages) . self::LINE_DELIMITER;
 
-            return str_split($message, $this->maxPayloadSize);
+            $result = str_split($message, $this->maxPayloadSize);
+
+            return $result ?: [];
         }
 
         $delimiterLen = strlen(self::LINE_DELIMITER);