diff --git a/.swift-version b/.swift-version
index 9f55b2c..2fe7a3f 100644
--- a/.swift-version
+++ b/.swift-version
@@ -1 +1 @@
-3.0
+3.1  
diff --git a/Example/Base.lproj/Main.storyboard b/Example/Base.lproj/Main.storyboard
index de34bc9..416d103 100644
--- a/Example/Base.lproj/Main.storyboard
+++ b/Example/Base.lproj/Main.storyboard
@@ -1,8 +1,11 @@
-<?xml version="1.0" encoding="UTF-8" standalone="no"?>
-<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="11201" systemVersion="15G31" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES" colorMatched="YES" initialViewController="1zI-So-CCp">
+<?xml version="1.0" encoding="UTF-8"?>
+<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="12118" systemVersion="16C67" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES" colorMatched="YES" initialViewController="1zI-So-CCp">
+    <device id="retina4_7" orientation="portrait">
+        <adaptation id="fullscreen"/>
+    </device>
     <dependencies>
         <deployment identifier="iOS"/>
-        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="11161"/>
+        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="12086"/>
         <capability name="documents saved in the Xcode 8 format" minToolsVersion="8.0"/>
     </dependencies>
     <scenes>
@@ -19,6 +22,7 @@
                         <autoresizingMask key="autoresizingMask" flexibleMaxX="YES" flexibleMaxY="YES"/>
                         <subviews>
                             <view tag="3" contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="ptD-fV-BOO" customClass="KYShutterButton" customModule="KYShutterButton">
+                                <rect key="frame" x="94.5" y="374.5" width="66" height="66"/>
                                 <color key="backgroundColor" red="0.0" green="0.0" blue="0.0" alpha="0.0" colorSpace="custom" customColorSpace="sRGB"/>
                                 <constraints>
                                     <constraint firstAttribute="width" constant="66" id="ERC-xB-Viu"/>
@@ -37,6 +41,7 @@
                                 </connections>
                             </view>
                             <view tag="2" contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="Vbb-QT-tAI" customClass="KYShutterButton" customModule="KYShutterButton">
+                                <rect key="frame" x="214.5" y="226.5" width="66" height="66"/>
                                 <color key="backgroundColor" red="0.0" green="0.0" blue="0.0" alpha="0.0" colorSpace="custom" customColorSpace="sRGB"/>
                                 <constraints>
                                     <constraint firstAttribute="width" constant="66" id="6rY-DD-cVE"/>
@@ -55,6 +60,7 @@
                                 </connections>
                             </view>
                             <view tag="3" contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="aLP-je-VrZ" customClass="KYShutterButton" customModule="KYShutterButton">
+                                <rect key="frame" x="214.5" y="374.5" width="66" height="66"/>
                                 <color key="backgroundColor" red="0.0" green="0.0" blue="0.0" alpha="0.0" colorSpace="custom" customColorSpace="sRGB"/>
                                 <constraints>
                                     <constraint firstAttribute="height" constant="66" id="Xc4-BE-Thk"/>
@@ -76,6 +82,7 @@
                                 </connections>
                             </view>
                             <view tag="1" contentMode="scaleToFill" translatesAutoresizingMaskIntoConstraints="NO" id="v1X-Iv-Kcs" customClass="KYShutterButton" customModule="KYShutterButton">
+                                <rect key="frame" x="94.5" y="226.5" width="66" height="66"/>
                                 <color key="backgroundColor" red="0.0" green="0.0" blue="0.0" alpha="0.0" colorSpace="custom" customColorSpace="sRGB"/>
                                 <constraints>
                                     <constraint firstAttribute="height" constant="66" id="1nr-Kg-YBL"/>
@@ -91,6 +98,7 @@
                                 </userDefinedRuntimeAttributes>
                             </view>
                             <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="Normal" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="sJU-SA-GY2">
+                                <rect key="frame" x="99.5" y="201" width="56" height="20.5"/>
                                 <constraints>
                                     <constraint firstAttribute="width" constant="56" id="PgG-H7-oNA"/>
                                 </constraints>
@@ -99,16 +107,19 @@
                                 <nil key="highlightedColor"/>
                             </label>
                             <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="SlowMotion" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="Fva-pz-owc">
+                                <rect key="frame" x="82" y="346" width="91" height="20.5"/>
                                 <fontDescription key="fontDescription" type="system" weight="light" pointSize="17"/>
                                 <color key="textColor" red="1" green="1" blue="1" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
                                 <nil key="highlightedColor"/>
                             </label>
                             <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="Normal" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="GLI-ZD-Cdd">
+                                <rect key="frame" x="219.5" y="201" width="56" height="20.5"/>
                                 <fontDescription key="fontDescription" type="system" weight="light" pointSize="17"/>
                                 <color key="textColor" red="1" green="1" blue="1" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
                                 <nil key="highlightedColor"/>
                             </label>
                             <label opaque="NO" userInteractionEnabled="NO" contentMode="left" horizontalHuggingPriority="251" verticalHuggingPriority="251" text="TimeLapse" lineBreakMode="tailTruncation" baselineAdjustment="alignBaselines" adjustsFontSizeToFit="NO" translatesAutoresizingMaskIntoConstraints="NO" id="aBT-ji-BYE">
+                                <rect key="frame" x="205" y="346" width="85" height="20.5"/>
                                 <constraints>
                                     <constraint firstAttribute="width" constant="85" id="gM8-zq-vZ4"/>
                                 </constraints>
diff --git a/KYShutterButton.podspec b/KYShutterButton.podspec
index 0f15b91..faae66e 100644
--- a/KYShutterButton.podspec
+++ b/KYShutterButton.podspec
@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
   s.name         = "KYShutterButton"
-  s.version      = "2.0.0"
+  s.version      = "2.0.1"
   s.summary      = "KYShutterButton is a custom button that is similar to the shutter button of the camera app"
   s.homepage     = "https://github.com/ykyouhei/KYShutterButton"
   s.license      = "MIT"
diff --git a/KYShutterButton/Classes/KYShutterButton.swift b/KYShutterButton/Classes/KYShutterButton.swift
index 85240bb..487a4ef 100644
--- a/KYShutterButton/Classes/KYShutterButton.swift
+++ b/KYShutterButton/Classes/KYShutterButton.swift
@@ -173,8 +173,8 @@ open class KYShutterButton: UIButton {
         return UIBezierPath(
             arcCenter: CGPoint(x: self.bounds.midX, y: self.bounds.midY),
             radius: self.bounds.width/2 - self._arcWidth/2,
-            startAngle: -CGFloat(M_PI_2),
-            endAngle: CGFloat(M_PI*2.0) - CGFloat(M_PI_2),
+            startAngle: -.pi/2,
+            endAngle: .pi*2 - .pi/2,
             clockwise: true
         )
     }
@@ -212,7 +212,7 @@ open class KYShutterButton: UIButton {
     private var _startRotateAnimation: CABasicAnimation {
         let animation         = CABasicAnimation(keyPath: "transform.rotation.z")
         animation.fromValue   = 0
-        animation.toValue     = CGFloat(M_PI*2.0)
+        animation.toValue     = CGFloat.pi*2
         animation.duration    = _kstartAnimateDuration
         return animation
     }
@@ -240,7 +240,7 @@ open class KYShutterButton: UIButton {
     private var _recordingRotateAnimation: CABasicAnimation {
         let animation         = CABasicAnimation(keyPath: "transform.rotation")
         animation.fromValue   = 0
-        animation.toValue     = CGFloat(M_PI*2.0)
+        animation.toValue     = CGFloat.pi*2
         animation.duration    = TimeInterval(rotateAnimateDuration)
         animation.repeatCount = Float.infinity
         animation.beginTime   = CACurrentMediaTime() + _kstartAnimateDuration
@@ -334,13 +334,13 @@ open class KYShutterButton: UIButton {
     }
     
     private func p_arcPathWithProgress(_ progress: CGFloat, clockwise: Bool = true) -> UIBezierPath {
-        let diameter = 2*CGFloat(M_PI)*(self.bounds.width/2 - self._arcWidth/3)
+        let diameter = 2*CGFloat.pi*(self.bounds.width/2 - self._arcWidth/3)
         let startAngle = clockwise ?
-            -CGFloat(M_PI_2) :
-            -CGFloat(M_PI_2) + CGFloat(M_PI)*(540/diameter)/180
+            -CGFloat.pi/2 :
+            -CGFloat.pi/2 + CGFloat.pi*(540/diameter)/180
         let endAngle   = clockwise ?
-            CGFloat(M_PI*2.0)*progress - CGFloat(M_PI_2) :
-            CGFloat(M_PI*2.0)*progress - CGFloat(M_PI_2) + CGFloat(M_PI)*(540/diameter)/180
+            CGFloat.pi*2*progress - CGFloat.pi/2 :
+            CGFloat.pi*2*progress - CGFloat.pi/2 + CGFloat.pi*(540/diameter)/180
         let path = UIBezierPath(
             arcCenter: CGPoint(x: self.bounds.midX, y: self.bounds.midY),
             radius: self.bounds.width/2 - self._arcWidth/3,
@@ -360,8 +360,8 @@ open class KYShutterButton: UIButton {
             _arcLayer.lineDashPattern = [1, 1]
             _progressLayer.isHidden     = true
         case .timeLapse:
-            let diameter = CGFloat(M_PI)*(self.bounds.width/2 - self._arcWidth/2)
-            let progressDiameter = 2*CGFloat(M_PI)*(self.bounds.width/2 - self._arcWidth/3)
+            let diameter = CGFloat.pi*(self.bounds.width/2 - self._arcWidth/2)
+            let progressDiameter = 2*CGFloat.pi*(self.bounds.width/2 - self._arcWidth/3)
             
             _arcLayer.lineDashPattern = [1, NSNumber(value: (diameter/10 - 1).native)]
             _progressLayer.lineDashPattern = [1, NSNumber(value: (progressDiameter/60 - 1).native)]
diff --git a/KYShutterButton/Info.plist b/KYShutterButton/Info.plist
index 7e7479f..783e22e 100644
--- a/KYShutterButton/Info.plist
+++ b/KYShutterButton/Info.plist
@@ -15,7 +15,7 @@
 	<key>CFBundlePackageType</key>
 	<string>FMWK</string>
 	<key>CFBundleShortVersionString</key>
-	<string>2.0.0</string>
+	<string>2.0.1</string>
 	<key>CFBundleSignature</key>
 	<string>????</string>
 	<key>CFBundleVersion</key>
diff --git a/README.md b/README.md
index dfdbc35..de93e07 100644
--- a/README.md
+++ b/README.md
@@ -4,7 +4,7 @@
 [![Pod Version](http://img.shields.io/cocoapods/v/KYShutterButton.svg?style=flat)](http://cocoadocs.org/docsets/KYShutterButton/) 
 [![Pod Platform](http://img.shields.io/cocoapods/p/KYShutterButton.svg?style=flat)](http://cocoadocs.org/docsets/KYShutterButton/)
 [![Pod License](http://img.shields.io/cocoapods/l/KYShutterButton.svg?style=flat)](https://github.com/ykyohei/KYShutterButton/blob/master/LICENSE) 
-![Swift version](https://img.shields.io/badge/swift-3.0-orange.svg)
+![Swift version](https://img.shields.io/badge/swift-3.1-orange.svg)
 
 
 `KYShutterButton` is a custom button that is similar to the shutter button of the camera app