diff --git a/.swift-version b/.swift-version
index bf77d54..819e07a 100644
--- a/.swift-version
+++ b/.swift-version
@@ -1 +1 @@
-4.2
+5.0
diff --git a/Example/Example.xcodeproj/project.pbxproj b/Example/Example.xcodeproj/project.pbxproj
index 8da0434..6a4bfe1 100644
--- a/Example/Example.xcodeproj/project.pbxproj
+++ b/Example/Example.xcodeproj/project.pbxproj
@@ -139,12 +139,12 @@
 			isa = PBXProject;
 			attributes = {
 				LastSwiftUpdateCheck = 0730;
-				LastUpgradeCheck = 1000;
+				LastUpgradeCheck = 1020;
 				ORGANIZATIONNAME = "Clipy Project";
 				TargetAttributes = {
 					312C0FC01D13AA0300973348 = {
 						CreatedOnToolsVersion = 7.3.1;
-						LastSwiftMigration = 0900;
+						LastSwiftMigration = 1020;
 					};
 				};
 			};
@@ -153,6 +153,7 @@
 			developmentRegion = English;
 			hasScannedForEncodings = 0;
 			knownRegions = (
+				English,
 				en,
 				Base,
 			);
@@ -236,6 +237,7 @@
 			isa = XCBuildConfiguration;
 			buildSettings = {
 				ALWAYS_SEARCH_USER_PATHS = NO;
+				CLANG_ANALYZER_LOCALIZABILITY_NONLOCALIZED = YES;
 				CLANG_ANALYZER_NONNULL = YES;
 				CLANG_CXX_LANGUAGE_STANDARD = "gnu++0x";
 				CLANG_CXX_LIBRARY = "libc++";
@@ -291,6 +293,7 @@
 			isa = XCBuildConfiguration;
 			buildSettings = {
 				ALWAYS_SEARCH_USER_PATHS = NO;
+				CLANG_ANALYZER_LOCALIZABILITY_NONLOCALIZED = YES;
 				CLANG_ANALYZER_NONNULL = YES;
 				CLANG_CXX_LANGUAGE_STANDARD = "gnu++0x";
 				CLANG_CXX_LIBRARY = "libc++";
@@ -345,8 +348,7 @@
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/../Frameworks";
 				PRODUCT_BUNDLE_IDENTIFIER = "com.clipy-app.Example";
 				PRODUCT_NAME = "$(TARGET_NAME)";
-				SWIFT_SWIFT3_OBJC_INFERENCE = Off;
-				SWIFT_VERSION = 4.0;
+				SWIFT_VERSION = 5.0;
 			};
 			name = Debug;
 		};
@@ -360,8 +362,7 @@
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/../Frameworks";
 				PRODUCT_BUNDLE_IDENTIFIER = "com.clipy-app.Example";
 				PRODUCT_NAME = "$(TARGET_NAME)";
-				SWIFT_SWIFT3_OBJC_INFERENCE = Off;
-				SWIFT_VERSION = 4.0;
+				SWIFT_VERSION = 5.0;
 			};
 			name = Release;
 		};
diff --git a/Lib/KeyHolder.xcodeproj/project.pbxproj b/Lib/KeyHolder.xcodeproj/project.pbxproj
index 9acf730..c25d4e3 100644
--- a/Lib/KeyHolder.xcodeproj/project.pbxproj
+++ b/Lib/KeyHolder.xcodeproj/project.pbxproj
@@ -231,12 +231,12 @@
 			isa = PBXProject;
 			attributes = {
 				LastSwiftUpdateCheck = 0730;
-				LastUpgradeCheck = 1000;
+				LastUpgradeCheck = 1020;
 				ORGANIZATIONNAME = "Clipy Project";
 				TargetAttributes = {
 					312C0FDA1D13AA1F00973348 = {
 						CreatedOnToolsVersion = 7.3.1;
-						LastSwiftMigration = 1000;
+						LastSwiftMigration = 1020;
 					};
 					312C0FE41D13AA1F00973348 = {
 						CreatedOnToolsVersion = 7.3.1;
@@ -249,6 +249,7 @@
 			developmentRegion = English;
 			hasScannedForEncodings = 0;
 			knownRegions = (
+				English,
 				en,
 			);
 			mainGroup = 312C0FD11D13AA1F00973348;
@@ -357,6 +358,7 @@
 			isa = XCBuildConfiguration;
 			buildSettings = {
 				ALWAYS_SEARCH_USER_PATHS = NO;
+				CLANG_ANALYZER_LOCALIZABILITY_NONLOCALIZED = YES;
 				CLANG_ANALYZER_NONNULL = YES;
 				CLANG_CXX_LANGUAGE_STANDARD = "gnu++0x";
 				CLANG_CXX_LIBRARY = "libc++";
@@ -415,6 +417,7 @@
 			isa = XCBuildConfiguration;
 			buildSettings = {
 				ALWAYS_SEARCH_USER_PATHS = NO;
+				CLANG_ANALYZER_LOCALIZABILITY_NONLOCALIZED = YES;
 				CLANG_ANALYZER_NONNULL = YES;
 				CLANG_CXX_LANGUAGE_STANDARD = "gnu++0x";
 				CLANG_CXX_LIBRARY = "libc++";
@@ -480,8 +483,7 @@
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				SKIP_INSTALL = YES;
 				SWIFT_OPTIMIZATION_LEVEL = "-Onone";
-				SWIFT_SWIFT3_OBJC_INFERENCE = Default;
-				SWIFT_VERSION = 4.2;
+				SWIFT_VERSION = 5.0;
 			};
 			name = Debug;
 		};
@@ -502,8 +504,7 @@
 				PRODUCT_BUNDLE_IDENTIFIER = "com.clipy-app.KeyHolder";
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				SKIP_INSTALL = YES;
-				SWIFT_SWIFT3_OBJC_INFERENCE = Default;
-				SWIFT_VERSION = 4.2;
+				SWIFT_VERSION = 5.0;
 			};
 			name = Release;
 		};
diff --git a/Lib/KeyHolder.xcodeproj/xcshareddata/xcschemes/KeyHolder.xcscheme b/Lib/KeyHolder.xcodeproj/xcshareddata/xcschemes/KeyHolder.xcscheme
index d99e746..029d192 100644
--- a/Lib/KeyHolder.xcodeproj/xcshareddata/xcschemes/KeyHolder.xcscheme
+++ b/Lib/KeyHolder.xcodeproj/xcshareddata/xcschemes/KeyHolder.xcscheme
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "1000"
+   LastUpgradeVersion = "1020"
    version = "1.3">
    <BuildAction
       parallelizeBuildables = "YES"
diff --git a/Lib/KeyHolder/RecordView.swift b/Lib/KeyHolder/RecordView.swift
index 83d1dc6..abb937b 100644
--- a/Lib/KeyHolder/RecordView.swift
+++ b/Lib/KeyHolder/RecordView.swift
@@ -320,8 +320,8 @@ public protocol RecordViewDelegate: class {
 }
 
 // MARK: - Text Attributes
-private extension RecordView {
-    func modifierTextAttributes(_ modifiers: NSEvent.ModifierFlags, checkModifier: NSEvent.ModifierFlags) -> [NSAttributedString.Key: Any] {
+extension RecordView {
+    fileprivate func modifierTextAttributes(_ modifiers: NSEvent.ModifierFlags, checkModifier: NSEvent.ModifierFlags) -> [NSAttributedString.Key: Any] {
         let paragraphStyle = NSMutableParagraphStyle()
         paragraphStyle.alignment = .center
         paragraphStyle.lineBreakMode = .byTruncatingTail
@@ -350,7 +350,7 @@ private extension RecordView {
 }
 
 // MARK: - Recording
-public extension RecordView {
+extension RecordView {
     public func beginRecording() -> Bool {
         if !isEnabled { return false }
         if isRecording { return true }
@@ -391,7 +391,7 @@ public extension RecordView {
 }
 
 // MARK: - Clear Keys
-public extension RecordView {
+extension RecordView {
     public func clear() {
         keyCombo = nil
         inputModifiers = NSEvent.ModifierFlags(rawValue: 0)
@@ -407,24 +407,24 @@ public extension RecordView {
 }
 
 // MARK: - Modifiers
-private extension RecordView {
-    func validateModifiers(_ modifiers: NSEvent.ModifierFlags?) -> Bool {
+extension RecordView {
+    fileprivate func validateModifiers(_ modifiers: NSEvent.ModifierFlags?) -> Bool {
         guard let modifiers = modifiers else { return false }
         return KeyTransformer.carbonFlags(from: modifiers) != 0
     }
 }
 
 // MARK: - Bool Extension
-private extension Bool {
-    var intValue: Int {
+extension Bool {
+    fileprivate var intValue: Int {
         return NSNumber(value: self).intValue
     }
 }
 
 // MARK: - NSColor Extensio
 // nmacOS 10.14 polyfill
-private extension NSColor {
-    static let controlAccentPolyfill: NSColor = {
+extension NSColor {
+    fileprivate static let controlAccentPolyfill: NSColor = {
         if #available(macOS 10.14, *) {
             return NSColor.controlAccentColor
         } else {