         var comfortVelocity = velocity
         comfortVelocity.x *= 2.0
         
-        let options: UIViewAnimationOptions
+        let options: UIView.AnimationOptions
         if abs(comfortVelocity.x) > 0 {
             options = .curveEaseOut
             duration = durationForDistance(distance: maxDistance, velocity: abs(comfortVelocity.x))
         }
         else {
-            options = UIViewAnimationOptions()
+            options = UIView.AnimationOptions()
             duration = defaultCancelPopDuration
         }
         

            }
        }
        else {
            options = UIViewAnimationOptions()
            duration = defaultCancelPopDuration
        }
        

    
    // MARK: UINavigationControllerDelegate
    
    public func navigationController(_ navigationController: UINavigationController, animationControllerFor operation: UINavigationController.Operation, from fromVC: UIViewController, to toVC: UIViewController) -> UIViewControllerAnimatedTransitioning? {
        if (isInteractivelyPopping && operation == .pop) {
            return interactivePopAnimator
        }
