How can I fix the "UIPopoverController is deprecated" warning?

You no longer need UIPopoverController for presenting a view controller.Instead you can set the modalPresentationStyle of view controller to UIModalPresentationPopover.

You can use the following code for that:

avc.modalPresentationStyle = UIModalPresentationPopover;avc.popoverPresentationController.sourceView = theButton;[self presentViewController:avc animated:YES completion:nil];

UIModalPresentationPopover

In a horizontally regular environment, a presentation style where the content is displayed in a popover view. The background content is dimmed and taps outside the popover cause the popover to be dismissed. If you do not want taps to dismiss the popover, you can assign one or more views to the passthroughViews property of the associated UIPopoverPresentationController object, which you can get from the popoverPresentationController property.

In a horizontally compact environment, this option behaves the same as UIModalPresentationFullScreen.

Available in iOS 8.0 and later.

Reference UIModalPresentationStyle Reference

You need to set either sourceView or barButtonItem property, else it will crash with the following message:

*** Terminating app due to uncaught exception 'NSGenericException', reason: 'UIPopoverPresentationController (***) should have a non-nil sourceView or barButtonItem set before the presentation occurs.'

For anchoring the popover arrow correctly, you need to specify the sourceRect property also.

avc.modalPresentationStyle                   = UIModalPresentationPopover;avc.popoverPresentationController.sourceView = self.view;avc.popoverPresentationController.sourceRect = theButton.frame;[self presentViewController:avc animated:YES completion:nil];

Refer sourceView and sourceRect for more details.

Apple has the official way to present and configure popovers for iOS8 here: https://developer.apple.com/library/ios/documentation/UIKit/Reference/UIPopoverPresentationController_class/index.html

While similar to @MidhunMP's answer, it's worth noting the paragraph:

Configuring the popover presentation controller after calling presentViewController:animated:completion: might seem counter-intuitive but UIKit does not create a presentation controller until after you initiate a presentation. In addition, UIKit must wait until the next update cycle to display new content onscreen anyway. That delay gives you time to configure the presentation controller for your popover.

Configuration and responding to events can also be done via a delegate if you wanted (https://developer.apple.com/library/ios/documentation/UIKit/Reference/UIPopoverPresentationControllerDelegate_protocol/index.html).

An example, setting aside the use of the delegate:

// Present the controller using the popover style.controller.modalPresentationStyle = UIModalPresentationPopover;[self presentViewController:controller animated:YES completion:nil];// Popover presentation controller was created when presenting; now  configure it.UIPopoverPresentationController *presentationController =        [controller popoverPresentationController];presentationController.permittedArrowDirections = UIPopoverArrowDirectionLeft;presentationController.sourceView = containerFrameOfReferenceView;// arrow points out of the rect specified herepresentationController.sourceRect = childOfContainerView.frame;

But you'll also want to dismiss this. To do so without using a delegate, your presenting controller can just call:

[self dismissViewControllerAnimated:YES completion:nil];

But what if I rotate my device, and the popover doesn't point to the right area? Your presenting controller can handle it:

// Respond to rotations or split screen changes- (void)viewWillTransitionToSize:(CGSize)size       withTransitionCoordinator:(id<UIViewControllerTransitionCoordinator>)coordinator {    [super viewWillTransitionToSize:size withTransitionCoordinator:coordinator];    [coordinator animateAlongsideTransition:nil                                  completion:^(id<UIViewControllerTransitionCoordinatorContext> _Nonnull context) {        // Fix up popover placement if necessary, after the transition.        if (self.presentedViewController) {            UIPopoverPresentationController *presentationController =                    [self.presentedViewController popoverPresentationController];            presentationController.sourceView = containerFrameOfReferenceView;            presentationController.sourceRect = childOfContainerView.frame;        }    }];}

If wanted directly from Button Action then this code can be used

SecondViewController *destinationViewController = (SecondViewController *)[self.storyboard instantiateViewControllerWithIdentifier:@"second"];destinationViewController.modalPresentationStyle = UIModalPresentationPopover;destinationViewController.popoverPresentationController.sourceView = self.customButton;// Set the correct sourceRect given the sender's boundsdestinationViewController.popoverPresentationController.sourceRect = ((UIView *)sender).bounds;[self presentViewController:destinationViewController animated:YES completion:nil];