diff --git a/phpstan.neon b/phpstan.neon
index 036a26e..4fbe348 100644
--- a/phpstan.neon
+++ b/phpstan.neon
@@ -5,6 +5,18 @@ includes:
 	- vendor/phpstan/phpstan-strict-rules/rules.neon
 
 parameters:
+	level: 9
+	phpVersion: 80000
+
+	scanDirectories:
+		- src
+
+	fileExtensions:
+		- php
+
+	paths:
+		- src
+
 	ignoreErrors:
 		-
 			message: "#^Call to deprecated method validateConfig\\(\\) of class Nette\\\\DI\\\\CompilerExtension\\:\nuse getConfigSchema\\(\\)$#"
diff --git a/src/DI/ComgateExtension.php b/src/DI/ComgateExtension.php
index 134ba74..7125043 100644
--- a/src/DI/ComgateExtension.php
+++ b/src/DI/ComgateExtension.php
@@ -7,7 +7,7 @@
 use Contributte\Comgate\Http\HttpClient;
 use GuzzleHttp\Client;
 use Nette\DI\CompilerExtension;
-use Nette\DI\Statement;
+use Nette\DI\Definitions\Statement;
 use Nette\Schema\Expect;
 use Nette\Schema\Schema;
 use stdClass;
diff --git a/src/DI/ComgateExtension24.php b/src/DI/ComgateExtension24.php
index bd3a0f7..401e4b1 100644
--- a/src/DI/ComgateExtension24.php
+++ b/src/DI/ComgateExtension24.php
@@ -7,7 +7,7 @@
 use Contributte\Comgate\Http\HttpClient;
 use GuzzleHttp\Client;
 use Nette\DI\CompilerExtension;
-use Nette\DI\Statement;
+use Nette\DI\Definitions\Statement;
 
 class ComgateExtension24 extends CompilerExtension
 {
diff --git a/src/Entity/Refund.php b/src/Entity/Refund.php
index 250e87c..a8797f7 100644
--- a/src/Entity/Refund.php
+++ b/src/Entity/Refund.php
@@ -17,8 +17,8 @@ class Refund extends AbstractEntity
 	/** @var string */
 	private $transId;
 
-    /** @var null|string */
-    private $refId;
+	/** @var string|null */
+	private $refId;
 
 	final private function __construct()
 	{
@@ -27,14 +27,14 @@ final private function __construct()
 	public static function of(
 		Money $money,
 		string $transId,
-        string $refId = null
+		?string $refId = null
 	): self
 	{
 		$p = new static();
 		$p->amount = $money->multipliedBy(100, RoundingMode::UNNECESSARY)->getAmount()->toInt();
 		$p->curr = $money->getCurrency()->getCurrencyCode();
 		$p->transId = $transId;
-        $p->refId = $refId;
+		$p->refId = $refId;
 
 		return $p;
 	}
@@ -54,11 +54,10 @@ public function getTransId(): string
 		return $this->transId;
 	}
 
-    public function getRefId(): string
-    {
-        return $this->refId;
-    }
-
+	public function getRefId(): ?string
+	{
+		return $this->refId;
+	}
 
 	/**
 	 * @return mixed[]
@@ -69,7 +68,7 @@ public function toArray(): array
 			'amount' => $this->amount,
 			'curr' => $this->curr,
 			'transId' => $this->transId,
-            'refId' => $this->refId,
+			'refId' => $this->refId,
 		];
 	}
 
diff --git a/src/Gateway/PaymentService.php b/src/Gateway/PaymentService.php
index a16acc7..80ddb85 100644
--- a/src/Gateway/PaymentService.php
+++ b/src/Gateway/PaymentService.php
@@ -32,17 +32,18 @@ public function status(PaymentStatus $status): Response
 		return $this->client->post('status', $status->toArray());
 	}
 
-    public function refund(Refund $payment): Response
-    {
-        $data = $payment->toArray();
+	public function refund(Refund $payment): Response
+	{
+		$data = $payment->toArray();
 
-        return $this->client->post('refund', $data);
-    }
+		return $this->client->post('refund', $data);
+	}
 
-    public function storno(Storno $payment): Response
-    {
-        $data = $payment->toArray();
+	public function storno(Storno $payment): Response
+	{
+		$data = $payment->toArray();
+
+		return $this->client->post('cancel', $data);
+	}
 
-        return $this->client->post('cancel', $data);
-    }
 }