diff --git a/HanziPinyin.xcodeproj/project.pbxproj b/HanziPinyin.xcodeproj/project.pbxproj
index 9845901..d01e828 100644
--- a/HanziPinyin.xcodeproj/project.pbxproj
+++ b/HanziPinyin.xcodeproj/project.pbxproj
@@ -122,7 +122,7 @@
 		D395A11C1CC244BB00B76FB7 /* Project object */ = {
 			isa = PBXProject;
 			attributes = {
-				LastUpgradeCheck = 0900;
+				LastUpgradeCheck = 0930;
 				ORGANIZATIONNAME = Teambition;
 				TargetAttributes = {
 					D395A1241CC244BB00B76FB7 = {
@@ -188,12 +188,14 @@
 				CLANG_WARN_BOOL_CONVERSION = YES;
 				CLANG_WARN_COMMA = YES;
 				CLANG_WARN_CONSTANT_CONVERSION = YES;
+				CLANG_WARN_DEPRECATED_OBJC_IMPLEMENTATIONS = YES;
 				CLANG_WARN_DIRECT_OBJC_ISA_USAGE = YES_ERROR;
 				CLANG_WARN_EMPTY_BODY = YES;
 				CLANG_WARN_ENUM_CONVERSION = YES;
 				CLANG_WARN_INFINITE_RECURSION = YES;
 				CLANG_WARN_INT_CONVERSION = YES;
 				CLANG_WARN_NON_LITERAL_NULL_CONVERSION = YES;
+				CLANG_WARN_OBJC_IMPLICIT_RETAIN_SELF = YES;
 				CLANG_WARN_OBJC_LITERAL_CONVERSION = YES;
 				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
 				CLANG_WARN_RANGE_LOOP_ANALYSIS = YES;
@@ -245,12 +247,14 @@
 				CLANG_WARN_BOOL_CONVERSION = YES;
 				CLANG_WARN_COMMA = YES;
 				CLANG_WARN_CONSTANT_CONVERSION = YES;
+				CLANG_WARN_DEPRECATED_OBJC_IMPLEMENTATIONS = YES;
 				CLANG_WARN_DIRECT_OBJC_ISA_USAGE = YES_ERROR;
 				CLANG_WARN_EMPTY_BODY = YES;
 				CLANG_WARN_ENUM_CONVERSION = YES;
 				CLANG_WARN_INFINITE_RECURSION = YES;
 				CLANG_WARN_INT_CONVERSION = YES;
 				CLANG_WARN_NON_LITERAL_NULL_CONVERSION = YES;
+				CLANG_WARN_OBJC_IMPLICIT_RETAIN_SELF = YES;
 				CLANG_WARN_OBJC_LITERAL_CONVERSION = YES;
 				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
 				CLANG_WARN_RANGE_LOOP_ANALYSIS = YES;
diff --git a/HanziPinyin.xcodeproj/xcshareddata/xcschemes/HanziPinyin.xcscheme b/HanziPinyin.xcodeproj/xcshareddata/xcschemes/HanziPinyin.xcscheme
index 6701ec0..90d572c 100644
--- a/HanziPinyin.xcodeproj/xcshareddata/xcschemes/HanziPinyin.xcscheme
+++ b/HanziPinyin.xcodeproj/xcshareddata/xcschemes/HanziPinyin.xcscheme
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "0900"
+   LastUpgradeVersion = "0930"
    version = "1.3">
    <BuildAction
       parallelizeBuildables = "YES"
@@ -26,7 +26,6 @@
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
-      language = ""
       shouldUseLaunchSchemeArgsEnv = "YES">
       <Testables>
       </Testables>
@@ -37,7 +36,6 @@
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
-      language = ""
       launchStyle = "0"
       useCustomWorkingDirectory = "NO"
       ignoresPersistentStateOnLaunch = "NO"
diff --git a/HanziPinyin.xcworkspace/xcshareddata/IDEWorkspaceChecks.plist b/HanziPinyin.xcworkspace/xcshareddata/IDEWorkspaceChecks.plist
new file mode 100644
index 0000000..18d9810
--- /dev/null
+++ b/HanziPinyin.xcworkspace/xcshareddata/IDEWorkspaceChecks.plist
@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>IDEDidComputeMac32BitWarning</key>
+	<true/>
+</dict>
+</plist>
diff --git a/HanziPinyin/String+HanziPinyin.swift b/HanziPinyin/String+HanziPinyin.swift
index fd77a42..f48cc2b 100644
--- a/HanziPinyin/String+HanziPinyin.swift
+++ b/HanziPinyin/String+HanziPinyin.swift
@@ -23,8 +23,8 @@ public extension String {
         }
 
         var pinyin = pinyinStrings.joined(separator: "")
-        if !pinyin.isEmpty && String(pinyin.suffix(from: pinyin.characters.index(pinyin.endIndex, offsetBy: -1))) == separator {
-            pinyin.remove(at: pinyin.characters.index(pinyin.endIndex, offsetBy: -1))
+        if !pinyin.isEmpty && String(pinyin.suffix(from: pinyin.index(pinyin.endIndex, offsetBy: -1))) == separator {
+            pinyin.remove(at: pinyin.index(pinyin.endIndex, offsetBy: -1))
         }
 
         return pinyin
@@ -46,7 +46,7 @@ public extension String {
             let pinyinArray = HanziPinyin.pinyinArray(withCharCodePoint: charCodePoint, outputFormat: outputFormat)
 
             if pinyinArray.count > 0 {
-                let acronym = pinyinArray.first!.characters.first!
+                let acronym = pinyinArray.first!.first!
                 pinyinStrings.append(String(acronym) + separator)
             } else {
                 pinyinStrings.append(String(unicodeScalar))
@@ -54,8 +54,8 @@ public extension String {
         }
 
         var pinyinAcronym = pinyinStrings.joined(separator: "")
-        if !pinyinAcronym.isEmpty && String(pinyinAcronym.suffix(from: pinyinAcronym.characters.index(pinyinAcronym.endIndex, offsetBy: -1))) == separator {
-            pinyinAcronym.remove(at: pinyinAcronym.characters.index(pinyinAcronym.endIndex, offsetBy: -1))
+        if !pinyinAcronym.isEmpty && String(pinyinAcronym.suffix(from: pinyinAcronym.index(pinyinAcronym.endIndex, offsetBy: -1))) == separator {
+            pinyinAcronym.remove(at: pinyinAcronym.index(pinyinAcronym.endIndex, offsetBy: -1))
         }
 
         return pinyinAcronym
diff --git a/HanziPinyin/Supporting Files/Info.plist b/HanziPinyin/Supporting Files/Info.plist
index 2a44702..2730238 100644
--- a/HanziPinyin/Supporting Files/Info.plist	
+++ b/HanziPinyin/Supporting Files/Info.plist	
@@ -15,7 +15,7 @@
 	<key>CFBundlePackageType</key>
 	<string>FMWK</string>
 	<key>CFBundleShortVersionString</key>
-	<string>0.0.5</string>
+	<string>0.0.6</string>
 	<key>CFBundleSignature</key>
 	<string>????</string>
 	<key>CFBundleVersion</key>
diff --git a/HanziPinyinExample.xcodeproj/project.pbxproj b/HanziPinyinExample.xcodeproj/project.pbxproj
index 0e8edc8..57713fc 100644
--- a/HanziPinyinExample.xcodeproj/project.pbxproj
+++ b/HanziPinyinExample.xcodeproj/project.pbxproj
@@ -111,7 +111,7 @@
 			isa = PBXProject;
 			attributes = {
 				LastSwiftUpdateCheck = 0730;
-				LastUpgradeCheck = 0900;
+				LastUpgradeCheck = 0930;
 				ORGANIZATIONNAME = Teambition;
 				TargetAttributes = {
 					D395A1051CC243DB00B76FB7 = {
@@ -188,12 +188,14 @@
 				CLANG_WARN_BOOL_CONVERSION = YES;
 				CLANG_WARN_COMMA = YES;
 				CLANG_WARN_CONSTANT_CONVERSION = YES;
+				CLANG_WARN_DEPRECATED_OBJC_IMPLEMENTATIONS = YES;
 				CLANG_WARN_DIRECT_OBJC_ISA_USAGE = YES_ERROR;
 				CLANG_WARN_EMPTY_BODY = YES;
 				CLANG_WARN_ENUM_CONVERSION = YES;
 				CLANG_WARN_INFINITE_RECURSION = YES;
 				CLANG_WARN_INT_CONVERSION = YES;
 				CLANG_WARN_NON_LITERAL_NULL_CONVERSION = YES;
+				CLANG_WARN_OBJC_IMPLICIT_RETAIN_SELF = YES;
 				CLANG_WARN_OBJC_LITERAL_CONVERSION = YES;
 				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
 				CLANG_WARN_RANGE_LOOP_ANALYSIS = YES;
@@ -242,12 +244,14 @@
 				CLANG_WARN_BOOL_CONVERSION = YES;
 				CLANG_WARN_COMMA = YES;
 				CLANG_WARN_CONSTANT_CONVERSION = YES;
+				CLANG_WARN_DEPRECATED_OBJC_IMPLEMENTATIONS = YES;
 				CLANG_WARN_DIRECT_OBJC_ISA_USAGE = YES_ERROR;
 				CLANG_WARN_EMPTY_BODY = YES;
 				CLANG_WARN_ENUM_CONVERSION = YES;
 				CLANG_WARN_INFINITE_RECURSION = YES;
 				CLANG_WARN_INT_CONVERSION = YES;
 				CLANG_WARN_NON_LITERAL_NULL_CONVERSION = YES;
+				CLANG_WARN_OBJC_IMPLICIT_RETAIN_SELF = YES;
 				CLANG_WARN_OBJC_LITERAL_CONVERSION = YES;
 				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
 				CLANG_WARN_RANGE_LOOP_ANALYSIS = YES;
diff --git a/HanziPinyinExample.xcodeproj/xcuserdata/hongxin.xcuserdatad/xcschemes/HanziPinyinExample.xcscheme b/HanziPinyinExample.xcodeproj/xcuserdata/hongxin.xcuserdatad/xcschemes/HanziPinyinExample.xcscheme
index f9d2854..105d801 100644
--- a/HanziPinyinExample.xcodeproj/xcuserdata/hongxin.xcuserdatad/xcschemes/HanziPinyinExample.xcscheme
+++ b/HanziPinyinExample.xcodeproj/xcuserdata/hongxin.xcuserdatad/xcschemes/HanziPinyinExample.xcscheme
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "0900"
+   LastUpgradeVersion = "0930"
    version = "1.3">
    <BuildAction
       parallelizeBuildables = "YES"
@@ -26,7 +26,6 @@
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
-      language = ""
       shouldUseLaunchSchemeArgsEnv = "YES">
       <Testables>
       </Testables>
@@ -46,7 +45,6 @@
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
-      language = ""
       launchStyle = "0"
       useCustomWorkingDirectory = "NO"
       ignoresPersistentStateOnLaunch = "NO"
diff --git a/HanziPinyinExample/HanziPinyinExampleViewController.swift b/HanziPinyinExample/HanziPinyinExampleViewController.swift
index b89a88b..078098f 100644
--- a/HanziPinyinExample/HanziPinyinExampleViewController.swift
+++ b/HanziPinyinExample/HanziPinyinExampleViewController.swift
@@ -58,7 +58,7 @@ class HanziPinyinExampleViewController: UIViewController {
     }
 
     @objc func inputTextFieldTextChanged(_ notification: Notification) {
-        pinyinButton.isEnabled = (inputTextField.text?.characters.count ?? 0) > 0
+        pinyinButton.isEnabled = (inputTextField.text?.count ?? 0) > 0
     }
 }
 
diff --git a/HanziPinyinExample/Info.plist b/HanziPinyinExample/Info.plist
index cd3eff8..492f5e4 100644
--- a/HanziPinyinExample/Info.plist
+++ b/HanziPinyinExample/Info.plist
@@ -15,11 +15,11 @@
 	<key>CFBundlePackageType</key>
 	<string>APPL</string>
 	<key>CFBundleShortVersionString</key>
-	<string>0.0.5</string>
+	<string>0.0.6</string>
 	<key>CFBundleSignature</key>
 	<string>????</string>
 	<key>CFBundleVersion</key>
-	<string>5</string>
+	<string>6</string>
 	<key>LSRequiresIPhoneOS</key>
 	<true/>
 	<key>UILaunchStoryboardName</key>