diff --git a/Headers/Foundation/NSBackgroundActivityScheduler.h b/Headers/Foundation/NSBackgroundActivityScheduler.h
index 1f93db348..35d9e5212 100644
--- a/Headers/Foundation/NSBackgroundActivityScheduler.h
+++ b/Headers/Foundation/NSBackgroundActivityScheduler.h
@@ -51,7 +51,7 @@ enum {
 };
 typedef NSInteger NSQualityOfService;
   
-@class NSString;
+@class NSString, NSTimer;
 
 DEFINE_BLOCK_TYPE(NSBackgroundActivityCompletionHandler, void, NSBackgroundActivityResult);
 DEFINE_BLOCK_TYPE(GSScheduledBlock, void, NSBackgroundActivityCompletionHandler);  
@@ -64,6 +64,7 @@ DEFINE_BLOCK_TYPE(GSScheduledBlock, void, NSBackgroundActivityCompletionHandler)
   NSTimeInterval _tolerance;
   BOOL _repeats;
   BOOL _shouldDefer;
+  NSTimer *_timer; 
 }
   
 - (instancetype) initWithIdentifier: (NSString *)identifier;
@@ -81,7 +82,7 @@ DEFINE_BLOCK_TYPE(GSScheduledBlock, void, NSBackgroundActivityCompletionHandler)
 - (void) setInterval: (NSTimeInterval)interval;
 
 - (NSTimeInterval) tolerance;
-- (void) setTolerance: (NSTimeInterval)interval;
+- (void) setTolerance: (NSTimeInterval)tolerance;
 
 - (BOOL) shouldDefer;
 - (void) setShouldDefer: (BOOL)flag;
diff --git a/Headers/Foundation/NSTimer.h b/Headers/Foundation/NSTimer.h
index 1ee7f6815..b2b2ceffa 100644
--- a/Headers/Foundation/NSTimer.h
+++ b/Headers/Foundation/NSTimer.h
@@ -28,6 +28,9 @@
 
 #import	<Foundation/NSDate.h>
 
+@class NSTimer;
+DEFINE_BLOCK_TYPE(GSTimerBlock, void, NSTimer*);
+
 #if	defined(__cplusplus)
 extern "C" {
 #endif
@@ -43,13 +46,14 @@ extern "C" {
 {
 #if	GS_EXPOSE(NSTimer)
 @public
-  NSDate 	*_date;		/* Must be first - for NSRunLoop optimisation */
-  BOOL		_invalidated;	/* Must be 2nd - for NSRunLoop optimisation */
-  BOOL		_repeats;
+  NSDate 	 *_date;	/* Must be 1st - for NSRunLoop optimisation */
+  BOOL		 _invalidated;	/* Must be 2nd - for NSRunLoop optimisation */
+  BOOL		 _repeats;
   NSTimeInterval _interval;
-  id		_target;
-  SEL		_selector;
-  id		_info;
+  id		 _target;
+  SEL		 _selector;
+  id		 _info;
+  GSTimerBlock   _block;
 #endif
 #if     GS_NONFRAGILE
 #else
@@ -67,15 +71,21 @@ extern "C" {
 + (NSTimer*) scheduledTimerWithTimeInterval: (NSTimeInterval)ti
 				 invocation: (NSInvocation*)invocation
 				    repeats: (BOOL)f;
+  
 + (NSTimer*) scheduledTimerWithTimeInterval: (NSTimeInterval)ti
 				     target: (id)object
 				   selector: (SEL)selector
 				   userInfo: (id)info
 				    repeats: (BOOL)f;
-
+  
++ (NSTimer *) scheduledTimerWithTimeInterval: (NSTimeInterval)ti
+                                     repeats: (BOOL)f
+                                       block: (GSTimerBlock)block;
+  
 + (NSTimer*) timerWithTimeInterval: (NSTimeInterval)ti
 		        invocation: (NSInvocation*)invocation
 			   repeats: (BOOL)f;
+
 + (NSTimer*) timerWithTimeInterval: (NSTimeInterval)ti
 			    target: (id)object
 			  selector: (SEL)selector
@@ -102,6 +112,13 @@ extern "C" {
 - (void) setFireDate: (NSDate*)fireDate;
 #endif
 
+#if	OS_API_VERSION(MAC_OS_X_VERSION_10_12, GS_API_LATEST)  
+- (instancetype)initWithFireDate:(NSDate *)date 
+                        interval:(NSTimeInterval)interval 
+                         repeats:(BOOL)repeats 
+                           block:(GSTimerBlock)block;
+#endif
+  
 @end
 
 #if	defined(__cplusplus)
diff --git a/Source/NSBackgroundActivityScheduler.m b/Source/NSBackgroundActivityScheduler.m
index edf0afd7e..fa9f4fd9d 100644
--- a/Source/NSBackgroundActivityScheduler.m
+++ b/Source/NSBackgroundActivityScheduler.m
@@ -37,6 +37,7 @@
       _interval = 0;
       _tolerance = 0;
       _shouldDefer = NO;
+      _timer = nil;
     }
   return self;
 }
@@ -103,6 +104,30 @@
 
 - (void) scheduleWithBlock: (GSScheduledBlock)block
 {
+  NSProcessInfo *pinfo = [NSProcessInfo processInfo];
+  id token = nil;
+  NSActivityOptions opts = 0;
+ 
+  switch(qualityOfService)
+    {
+    case NSQualityOfServiceUserInteractive:
+      opts = NSActivityUserInitiated | NSActivityIdleDisplaySleepDisabled;
+      break;
+    case NSQualityOfServiceUserInitiated:
+      opts = NSActivityUserInitiated;
+      break;
+    case NSQualityOfServiceUtility:
+      opts = NSActivityUserInitiated | NSActivityIdleDisplaySleepDisabled;
+      break;
+    case NSQualityOfServiceBackground:
+      opts = NSActivityBackground;
+      break;
+    case NSQualityOfServiceDefault:
+      opts = NSActivityLatencyCritical;
+      break;
+    }
+
+  token = [pinfo beginActivityWithOptions: 
 }
 
 - (void) invalidate
diff --git a/Source/NSTimer.m b/Source/NSTimer.m
index 4173d6cd1..ca0823fe8 100644
--- a/Source/NSTimer.m
+++ b/Source/NSTimer.m
@@ -145,6 +145,20 @@ static Class	NSDate_class;
   return self;
 }
 
+- (instancetype)initWithFireDate:(NSDate *)date 
+                        interval:(NSTimeInterval)interval 
+                         repeats:(BOOL)repeats 
+                           block:(GSTimerBlock)block
+{
+  return [self initWithFireDate: date
+                       interval: interval
+                         target: nil
+                       selector: NULL
+                       userInfo: nil
+                        repeats: repeats];
+  ASSIGN(_block, block);
+}
+
 /**
  * Create a timer which will fire after ti seconds and, if f is YES,
  * every ti seconds thereafter. On firing, invocation will be performed.<br />
@@ -229,6 +243,19 @@ static Class	NSDate_class;
   return t;
 }
 
++ (NSTimer *) scheduledTimerWithTimeInterval: (NSTimeInterval)ti
+                                     repeats: (BOOL)f
+                                       block: (GSTimerBlock)block
+{
+  id t = [[self alloc] initWithFireDate: nil
+                               interval: ti
+                                repeats: f
+                                  block: block];
+  [[NSRunLoop currentRunLoop] addTimer: t forMode: NSDefaultRunLoopMode];
+  RELEASE(t);
+  return t;  
+}
+
 - (void) dealloc
 {
   if (_invalidated == NO)
@@ -251,48 +278,56 @@ static Class	NSDate_class;
    */
   if (NO == _invalidated)
     {
-      id	target;
-
-      /* We retain the target so it won't be deallocated while we are using it
-       * (if this timer gets invalidated while we are firing).
-       */
-      target = RETAIN(_target);
-
-      if (_selector == 0)
-	{
-	  NS_DURING
-	    {
-	      [(NSInvocation*)target invoke];
-	    }
-	  NS_HANDLER
-	    {
-	      NSLog(@"*** NSTimer ignoring exception '%@' (reason '%@') "
-	        @"raised during posting of timer with target %s(%s) "
-		@"and selector '%@'",
-		[localException name], [localException reason],
-                GSClassNameFromObject(target),
-                GSObjCIsInstance(target) ? "instance" : "class",
-		NSStringFromSelector([target selector]));
-	    }
-	  NS_ENDHANDLER
-	}
+      if(_block != nil)
+        {
+          CALL_BLOCK(_block, self);
+        }
       else
-	{
-	  NS_DURING
-	    {
-	      [target performSelector: _selector withObject: self];
-	    }
-	  NS_HANDLER
-	    {
-	      NSLog(@"*** NSTimer ignoring exception '%@' (reason '%@') "
-		@"raised during posting of timer with target %p and "
-		@"selector '%@'",
-		[localException name], [localException reason], target,
-		NSStringFromSelector(_selector));
-	    }
-	  NS_ENDHANDLER
-	}
-      RELEASE(target);
+        {
+          id	target;
+          
+          /* We retain the target so it won't be deallocated while we are using it
+           * (if this timer gets invalidated while we are firing).
+           */
+          target = RETAIN(_target);
+          
+          if (_selector == 0)
+            {
+              NS_DURING
+                {
+                  [(NSInvocation*)target invoke];
+                }
+              NS_HANDLER
+                {
+                  NSLog(@"*** NSTimer ignoring exception '%@' (reason '%@') "
+                        @"raised during posting of timer with target %s(%s) "
+                        @"and selector '%@'",
+                        [localException name], [localException reason],
+                        GSClassNameFromObject(target),
+                        GSObjCIsInstance(target) ? "instance" : "class",
+                        NSStringFromSelector([target selector]));
+                }
+              NS_ENDHANDLER
+                }
+          else
+            {
+              NS_DURING
+                {
+                  [target performSelector: _selector withObject: self];
+                }
+              NS_HANDLER
+                {
+                  NSLog(@"*** NSTimer ignoring exception '%@' (reason '%@') "
+                        @"raised during posting of timer with target %p and "
+                        @"selector '%@'",
+                        [localException name], [localException reason], target,
+                        NSStringFromSelector(_selector));
+                }
+              NS_ENDHANDLER
+                }
+          RELEASE(target);
+        }
+      
       if (_repeats == NO)
         {
           [self invalidate];