Load popup dialog in iOS

Now after launch of iOS8, I found problem in executing same code that was previously worked fine.

At present for my game I have used following code

     float sysVer = [[[UIDevice currentDevice] systemVersion] floatValue];
     if (sysVer  < 8.0) {
         [[UIApplication sharedApplication].keyWindow.rootViewController presentViewController:activityVc animated:YES completion:nil];
     } else {
        
         UIPopoverController *popup = [[UIPopoverController alloc] initWithContentViewController:activityVc];
         [popup presentPopoverFromRect:CGRectMake(self.view.frame.size.width/2, self.view.frame.size.height/4, 0, 0)inView:[UIApplication sharedApplication].keyWindow.rootViewController.view permittedArrowDirections:UIPopoverArrowDirectionAny animated:YES];
        
     }

Following is scenario for different devices

iPod with iOS Version 6.0 : Works perfectly - Mine

iPad with iOS Version 8.0 : Works perfectly - Mine

iPhone 6 with iOS Version 8.2 : Not Working - Client

Last device is of client and he has detected exception in his device. So that I didn't have any logcat details.

Please give me some suggestion what is going wrong in my code!!!