@@ -14,10 +14,12 @@
  * file.
  */
 
 #import "OFObject.h"
 
+OF_ASSUME_NONNULL_BEGIN
+
 /*! @file */
 
 @class OFTimer;
 @class OFDate;
 @class OFRunLoop;
@@ -87,11 +89,11 @@
  * @return A new, autoreleased timer
  */
 + (instancetype)scheduledTimerWithTimeInterval: (of_time_interval_t)timeInterval
 					target: (id)target
 				      selector: (SEL)selector
-					object: (id)object
+					object: (nullable id)object
 				       repeats: (bool)repeats;
 
 /*!
  * @brief Creates and schedules a new timer with the specified time interval.
  *
@@ -106,12 +108,12 @@
  * @return A new, autoreleased timer
  */
 + (instancetype)scheduledTimerWithTimeInterval: (of_time_interval_t)timeInterval
 					target: (id)target
 				      selector: (SEL)selector
-					object: (id)object1
-					object: (id)object2
+					object: (nullable id)object1
+					object: (nullable id)object2
 				       repeats: (bool)repeats;
 
 #ifdef OF_HAVE_BLOCKS
 /*!
  * @brief Creates and schedules a new timer with the specified time interval.
@@ -151,11 +153,11 @@
  * @return A new, autoreleased timer
  */
 + (instancetype)timerWithTimeInterval: (of_time_interval_t)timeInterval
 			       target: (id)target
 			     selector: (SEL)selector
-			       object: (id)object
+			       object: (nullable id)object
 			      repeats: (bool)repeats;
 
 /*!
  * @brief Creates a new timer with the specified time interval.
  *
@@ -170,12 +172,12 @@
  * @return A new, autoreleased timer
  */
 + (instancetype)timerWithTimeInterval: (of_time_interval_t)timeInterval
 			       target: (id)target
 			     selector: (SEL)selector
-			       object: (id)object1
-			       object: (id)object2
+			       object: (nullable id)object1
+			       object: (nullable id)object2
 			      repeats: (bool)repeats;
 
 #ifdef OF_HAVE_BLOCKS
 /*!
  * @brief Creates a new timer with the specified time interval.
@@ -223,11 +225,11 @@
  */
 - initWithFireDate: (OFDate*)fireDate
 	  interval: (of_time_interval_t)interval
 	    target: (id)target
 	  selector: (SEL)selector
-	    object: (id)object
+	    object: (nullable id)object
 	   repeats: (bool)repeats;
 
 /*!
  * @brief Initializes an already allocated timer with the specified time
  *	  interval.
@@ -246,12 +248,12 @@
  */
 - initWithFireDate: (OFDate*)fireDate
 	  interval: (of_time_interval_t)interval
 	    target: (id)target
 	  selector: (SEL)selector
-	    object: (id)object1
-	    object: (id)object2
+	    object: (nullable id)object1
+	    object: (nullable id)object2
 	   repeats: (bool)repeats;
 
 #ifdef OF_HAVE_BLOCKS
 /*!
  * @brief Initializes an already allocated timer with the specified time
@@ -321,5 +323,7 @@
  * @brief Waits until the timer fired.
  */
 - (void)waitUntilDone;
 #endif
 @end
+
+OF_ASSUME_NONNULL_END