diff --git a/src/Overlay/InfoWindow.php b/src/Overlay/InfoWindow.php
index c8c9986f..86ba1849 100644
--- a/src/Overlay/InfoWindow.php
+++ b/src/Overlay/InfoWindow.php
@@ -72,7 +72,7 @@ class InfoWindow implements ExtendableInterface, OptionsAwareInterface
      * @param string $content
      * @param string $type
      */
-    public function __construct($content, $type = InfoWindowType::DEFAULT_, Coordinate $position = null)
+    public function __construct($content, $type = InfoWindowType::DEFAULT_, ?Coordinate $position = null)
     {
         $this->setContent($content);
         $this->setType($type);
@@ -127,7 +127,7 @@ public function getPosition()
         return $this->position;
     }
 
-    public function setPosition(Coordinate $position = null)
+    public function setPosition(?Coordinate $position = null)
     {
         $this->position = $position;
     }
@@ -148,7 +148,7 @@ public function getPixelOffset()
         return $this->pixedOffset;
     }
 
-    public function setPixelOffset(Size $pixelOffset = null)
+    public function setPixelOffset(?Size $pixelOffset = null)
     {
         $this->pixedOffset = $pixelOffset;
     }
diff --git a/src/Service/AbstractService.php b/src/Service/AbstractService.php
index 0676dadc..8e12d986 100644
--- a/src/Service/AbstractService.php
+++ b/src/Service/AbstractService.php
@@ -88,7 +88,7 @@ public function hasBusinessAccount()
     }
 
     /**
-     * @return BusinessAccount
+     * @return ?BusinessAccount
      */
     public function getBusinessAccount()
     {
@@ -96,9 +96,9 @@ public function getBusinessAccount()
     }
 
     /**
-     * @param BusinessAccount $businessAccount
+     * @param ?BusinessAccount $businessAccount
      */
-    public function setBusinessAccount(BusinessAccount $businessAccount = null)
+    public function setBusinessAccount(?BusinessAccount $businessAccount = null)
     {
         $this->businessAccount = $businessAccount;
     }