diff --git a/HELargeCenterTabBarController.podspec b/HELargeCenterTabBarController.podspec
index 94060a4..7f754c0 100644
--- a/HELargeCenterTabBarController.podspec
+++ b/HELargeCenterTabBarController.podspec
@@ -7,14 +7,14 @@ Pod::Spec.new do |spec|
   spec.author               = { 'John C. Daub (@hsoi)' => 'hsoi@hsoienterprises.com' }
   spec.social_media_url     = 'https://twitter.com/hsoienterprises'
   spec.description          = <<-DESC
-                        HELargeCenterTabBarController is a 100% Swift implementation of a UITabBarController with a lager center tab. 
+                        HELargeCenterTabBarController is a 100% Swift implementation of a UITabBarController with a lager center tab.
                         The center tab can be used in the typical manner where a tap switches to display the associated ViewController, or the center tab can be used in an alternate manner where the tap does not switch ViewControllers but instead executes a target-action.
-                        
+
                         Simple. Lightweight. To-the-point.
                         DESC
   spec.requires_arc         = true
   spec.license              = { :type => 'BSD 3-clause “New” or “Revised”', :file => 'LICENSE' }
   spec.source_files         = ['HELargeCenterTabBarController/*.swift', 'HELargeCenterTabBarController/*.h']
-  spec.platform             = :ios, '8.0'
+  spec.platform             = :ios, '9.0'
   spec.module_name          = 'HELargeCenterTabBarController'
 end
diff --git a/HELargeCenterTabBarController.xcodeproj/project.pbxproj b/HELargeCenterTabBarController.xcodeproj/project.pbxproj
index 24101c0..ae69c94 100644
--- a/HELargeCenterTabBarController.xcodeproj/project.pbxproj
+++ b/HELargeCenterTabBarController.xcodeproj/project.pbxproj
@@ -378,7 +378,7 @@
 				GCC_WARN_UNINITIALIZED_AUTOS = YES_AGGRESSIVE;
 				GCC_WARN_UNUSED_FUNCTION = YES;
 				GCC_WARN_UNUSED_VARIABLE = YES;
-				IPHONEOS_DEPLOYMENT_TARGET = 8.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 9.0;
 				MTL_ENABLE_DEBUG_INFO = YES;
 				ONLY_ACTIVE_ARCH = YES;
 				RUN_CLANG_STATIC_ANALYZER = YES;
@@ -430,7 +430,7 @@
 				GCC_WARN_UNINITIALIZED_AUTOS = YES_AGGRESSIVE;
 				GCC_WARN_UNUSED_FUNCTION = YES;
 				GCC_WARN_UNUSED_VARIABLE = YES;
-				IPHONEOS_DEPLOYMENT_TARGET = 8.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 9.0;
 				MTL_ENABLE_DEBUG_INFO = NO;
 				RUN_CLANG_STATIC_ANALYZER = YES;
 				SDKROOT = iphoneos;
diff --git a/HELargeCenterTabBarController/HELargeCenterTabBarController.swift b/HELargeCenterTabBarController/HELargeCenterTabBarController.swift
index a99a7e8..a6d5507 100644
--- a/HELargeCenterTabBarController/HELargeCenterTabBarController.swift
+++ b/HELargeCenterTabBarController/HELargeCenterTabBarController.swift
@@ -144,20 +144,20 @@ class HELargeCenterTabBarController: UITabBarController {
         let button = UIButton(type: .custom)
         button.translatesAutoresizingMaskIntoConstraints = false
         tabBar.addSubview(button)
-        
+      
+        let bottomAnchor: NSLayoutYAxisAnchor
         if #available(iOS 11.0, *) {
-            NSLayoutConstraint.activate([
-                button.centerXAnchor.constraint(equalTo: view.centerXAnchor),
-                button.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor),
-                button.widthAnchor.constraint(equalToConstant: unselectedImage.size.width),
-                button.heightAnchor.constraint(equalToConstant: unselectedImage.size.height)
-            ])
+          bottomAnchor = tabBar.safeAreaLayoutGuide.bottomAnchor
         } else {
-            view.addConstraint(NSLayoutConstraint(item: button, attribute: NSLayoutAttribute.centerX, relatedBy: NSLayoutRelation.equal, toItem: view, attribute: NSLayoutAttribute.centerX, multiplier: 1.0, constant: 0.0))
-            view.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:[button]-0-|", options: NSLayoutFormatOptions(rawValue: 0), metrics: nil, views: ["button": button]));
-            view.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "H:[button(==\(unselectedImage.size.width))]", options: NSLayoutFormatOptions(rawValue: 0), metrics: nil, views: ["button": button]))
-            view.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:[button(==\(unselectedImage.size.height))]", options: NSLayoutFormatOptions(rawValue: 0), metrics: nil, views: ["button": button]))
+          bottomAnchor = tabBar.bottomAnchor
         }
+      
+        NSLayoutConstraint.activate([
+            button.centerXAnchor.constraint(equalTo: tabBar.centerXAnchor),
+            button.bottomAnchor.constraint(equalTo: bottomAnchor),
+            button.widthAnchor.constraint(equalToConstant: unselectedImage.size.width),
+            button.heightAnchor.constraint(equalToConstant: unselectedImage.size.height)
+          ])
         
         button.addTarget(self, action: #selector(centerButtonAction(_:)), for: .touchUpInside)
         centerButton = button