@@ -68,11 +68,11 @@
  *
  * @return A new, autoreleased undefined key exception
  */
 + (instancetype)exceptionWithObject: (id)object
 				key: (OFString *)key
-			      value: (id)value;
+			      value: (nullable id)value;
 
 - init OF_UNAVAILABLE;
 
 /*!
  * @brief Initializes an already allocated undefined key exception.
@@ -94,9 +94,9 @@
  *
  * @return An initialized undefined key exception
  */
 - initWithObject: (id)object
 	     key: (OFString *)key
-	   value: (id)value;
+	   value: (nullable id)value OF_DESIGNATED_INITIALIZER;
 @end
 
 OF_ASSUME_NONNULL_END