diff --git a/NGVolumeControl/NGVolumeControl.xcodeproj/project.pbxproj b/NGVolumeControl/NGVolumeControl.xcodeproj/project.pbxproj
index 285dd05..5827248 100644
--- a/NGVolumeControl/NGVolumeControl.xcodeproj/project.pbxproj
+++ b/NGVolumeControl/NGVolumeControl.xcodeproj/project.pbxproj
@@ -145,7 +145,7 @@
 		9BCC745614FCCE8C004F30FF /* Project object */ = {
 			isa = PBXProject;
 			attributes = {
-				LastUpgradeCheck = 0500;
+				LastUpgradeCheck = 0600;
 				ORGANIZATIONNAME = "NOUS Wissensmanagement GmbH";
 			};
 			buildConfigurationList = 9BCC745914FCCE8C004F30FF /* Build configuration list for PBXProject "NGVolumeControl" */;
@@ -188,8 +188,10 @@
 				CLANG_WARN_EMPTY_BODY = YES;
 				CLANG_WARN_ENUM_CONVERSION = YES;
 				CLANG_WARN_INT_CONVERSION = YES;
+				CLANG_WARN_UNREACHABLE_CODE = YES;
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
 				COPY_PHASE_STRIP = NO;
+				ENABLE_STRICT_OBJC_MSGSEND = YES;
 				GCC_C_LANGUAGE_STANDARD = gnu99;
 				GCC_DYNAMIC_NO_PIC = NO;
 				GCC_OPTIMIZATION_LEVEL = 0;
@@ -222,8 +224,10 @@
 				CLANG_WARN_EMPTY_BODY = YES;
 				CLANG_WARN_ENUM_CONVERSION = YES;
 				CLANG_WARN_INT_CONVERSION = YES;
+				CLANG_WARN_UNREACHABLE_CODE = YES;
 				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
 				COPY_PHASE_STRIP = YES;
+				ENABLE_STRICT_OBJC_MSGSEND = YES;
 				GCC_C_LANGUAGE_STANDARD = gnu99;
 				GCC_VERSION = com.apple.compilers.llvm.clang.1_0;
 				GCC_WARN_64_TO_32_BIT_CONVERSION = YES;
diff --git a/NGVolumeControl/NGVolumeControl/NGVolumeControl.m b/NGVolumeControl/NGVolumeControl/NGVolumeControl.m
index 6e2e1bf..710d737 100644
--- a/NGVolumeControl/NGVolumeControl/NGVolumeControl.m
+++ b/NGVolumeControl/NGVolumeControl/NGVolumeControl.m
@@ -22,6 +22,7 @@ @interface NGVolumeControl ()
 @property (nonatomic, strong) UIView *sliderView;
 @property (nonatomic, strong) NGVolumeSlider *slider;
 @property (nonatomic, assign) float systemVolume;
+@property (nonatomic, assign) float currentSystemVolume;
 @property (nonatomic, readonly) BOOL sliderVisible;
 
 @property (nonatomic, assign) CGPoint touchStartPoint;
@@ -101,6 +102,8 @@ - (id)initWithFrame:(CGRect)frame {
 
             CGPathRelease(path);
         }
+        
+        self.currentSystemVolume = self.systemVolume;
 
         // observe changes to system volume (volume buttons)
         [[NSNotificationCenter defaultCenter] addObserver:self
@@ -388,7 +391,13 @@ - (void)customizeSlider:(UISlider *)slider {
 
 - (void)setSystemVolume:(float)systemVolume {
     MPMusicPlayerController *musicPlayer = [MPMusicPlayerController iPodMusicPlayer];
+    
+    if ([self.volumeDelegate respondsToSelector:@selector(volumeControl:didChangeOldVolume:toNewVolume:)]) {
+        [self.volumeDelegate volumeControl:self didChangeOldVolume:musicPlayer.volume toNewVolume:systemVolume];
+    }
+    
     musicPlayer.volume = systemVolume;
+    self.currentSystemVolume = systemVolume;
 }
 
 - (float)systemVolume {
@@ -544,6 +553,11 @@ - (void)updateUI {
 
 - (void)systemVolumeChanged:(NSNotification *)notification {
     // we update the UI when the system volume changed (volume buttons)
+    if ([self.volumeDelegate respondsToSelector:@selector(volumeControl:didChangeOldVolume:toNewVolume:)]) {
+        float newVolume = [notification.userInfo[@"AVSystemController_AudioVolumeNotificationParameter"] floatValue];
+        [self.volumeDelegate volumeControl:self didChangeOldVolume:self.currentSystemVolume toNewVolume:newVolume];
+        self.currentSystemVolume = newVolume;
+    }
     [self updateUI];
 }
 
diff --git a/NGVolumeControl/NGVolumeControl/NGVolumeControlDelegate.h b/NGVolumeControl/NGVolumeControl/NGVolumeControlDelegate.h
index 27683d1..560e598 100644
--- a/NGVolumeControl/NGVolumeControl/NGVolumeControlDelegate.h
+++ b/NGVolumeControl/NGVolumeControl/NGVolumeControlDelegate.h
@@ -20,5 +20,6 @@
 - (void)volumeControlDidExpand:(NGVolumeControl *)volumeControl;
 - (void)volumeControlWillShrink:(NGVolumeControl *)volumeControl;
 - (void)volumeControlDidShrink:(NGVolumeControl *)volumeControl;
+- (void)volumeControl:(NGVolumeControl *)volumeControl didChangeOldVolume:(float)oldVolume toNewVolume:(float)newVolume;
 
 @end