diff --git a/Mpdf/Image/ImageProcessor.php b/Mpdf/Image/ImageProcessor.php
index 60a4304..c16ca3a 100755
--- a/Mpdf/Image/ImageProcessor.php
+++ b/Mpdf/Image/ImageProcessor.php
@@ -141,7 +141,7 @@ class ImageProcessor implements \Psr\Log\LoggerAwareInterface
 	/**
 	 * @param \Psr\Log\LoggerInterface
 	 *
-	 * @return self
+	 * @return void
 	 */
 	public function setLogger(LoggerInterface $logger)
 	{
diff --git a/Mpdf/Mpdf.php b/Mpdf/Mpdf.php
index ec3280b..2a05b35 100755
--- a/Mpdf/Mpdf.php
+++ b/Mpdf/Mpdf.php
@@ -1552,7 +1552,7 @@ class Mpdf implements \Psr\Log\LoggerAwareInterface
 	/**
 	 * {@inheritdoc}
 	 */
-	public function setLogger(LoggerInterface $logger) : void
+	public function setLogger(LoggerInterface $logger)
 	{
 		$this->logger = $logger;
 
diff --git a/Mpdf/SizeConverter.php b/Mpdf/SizeConverter.php
index 217d4aa..9ec93fd 100755
--- a/Mpdf/SizeConverter.php
+++ b/Mpdf/SizeConverter.php
@@ -30,7 +30,7 @@ class SizeConverter implements \Psr\Log\LoggerAwareInterface
 		$this->logger = $logger;
 	}
 
-	public function setLogger(LoggerInterface $logger) : void
+	public function setLogger(LoggerInterface $logger)
 	{
 		$this->logger = $logger;
 	}
diff --git a/Psr/Log/LoggerAwareInterface.php b/Psr/Log/LoggerAwareInterface.php
index 7fbd757..4d64f47 100755
--- a/Psr/Log/LoggerAwareInterface.php
+++ b/Psr/Log/LoggerAwareInterface.php
@@ -14,5 +14,5 @@ interface LoggerAwareInterface
      *
      * @return void
      */
-    public function setLogger(LoggerInterface $logger) : void;
+    public function setLogger(LoggerInterface $logger);
 }