@@ -13,10 +13,12 @@
  * LICENSE.GPLv2 or LICENSE.GPLv3 respectively included in the packaging of this
  * file.
  */
 
 #import "OFObject.h"
+
+OF_ASSUME_NONNULL_BEGIN
 
 #define OF_SERIALIZATION_NS @"https://webkeks.org/objfw/serialization"
 
 @class OFXMLElement;
 
@@ -39,5 +41,7 @@
  *
  * @return The object serialized into an XML element
  */
 - (OFXMLElement*)XMLElementBySerializing;
 @end
+
+OF_ASSUME_NONNULL_END