diff --git a/NohanaImagePicker.xcodeproj/project.pbxproj b/NohanaImagePicker.xcodeproj/project.pbxproj
index 4598b76..6d1b2cb 100644
--- a/NohanaImagePicker.xcodeproj/project.pbxproj
+++ b/NohanaImagePicker.xcodeproj/project.pbxproj
@@ -318,11 +318,11 @@
 				TargetAttributes = {
 					F208E5501CD7370B00FFC9F6 = {
 						CreatedOnToolsVersion = 7.2.1;
-						LastSwiftMigration = 0800;
+						LastSwiftMigration = 0900;
 					};
 					F2C08D731C68651900B00181 = {
 						CreatedOnToolsVersion = 7.2.1;
-						LastSwiftMigration = 0800;
+						LastSwiftMigration = 0900;
 					};
 				};
 			};
@@ -462,7 +462,8 @@
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks";
 				PRODUCT_BUNDLE_IDENTIFIER = jp.co.nohana.NohanaImagePicker.Demo;
 				PRODUCT_NAME = "$(TARGET_NAME)";
-				SWIFT_VERSION = 3.0;
+				SWIFT_SWIFT3_OBJC_INFERENCE = On;
+				SWIFT_VERSION = 4.0;
 			};
 			name = Debug;
 		};
@@ -476,7 +477,8 @@
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks";
 				PRODUCT_BUNDLE_IDENTIFIER = jp.co.nohana.NohanaImagePicker.Demo;
 				PRODUCT_NAME = "$(TARGET_NAME)";
-				SWIFT_VERSION = 3.0;
+				SWIFT_SWIFT3_OBJC_INFERENCE = On;
+				SWIFT_VERSION = 4.0;
 			};
 			name = Release;
 		};
@@ -607,7 +609,8 @@
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				SKIP_INSTALL = YES;
 				SWIFT_OPTIMIZATION_LEVEL = "-Onone";
-				SWIFT_VERSION = 3.0;
+				SWIFT_SWIFT3_OBJC_INFERENCE = On;
+				SWIFT_VERSION = 4.0;
 			};
 			name = Debug;
 		};
@@ -627,7 +630,8 @@
 				PRODUCT_BUNDLE_IDENTIFIER = jp.co.nohana.NohanaImagePicker;
 				PRODUCT_NAME = "$(TARGET_NAME)";
 				SKIP_INSTALL = YES;
-				SWIFT_VERSION = 3.0;
+				SWIFT_SWIFT3_OBJC_INFERENCE = On;
+				SWIFT_VERSION = 4.0;
 			};
 			name = Release;
 		};
diff --git a/NohanaImagePicker/AlbumListEmptyIndicator.swift b/NohanaImagePicker/AlbumListEmptyIndicator.swift
index 2f6f934..492d4c9 100644
--- a/NohanaImagePicker/AlbumListEmptyIndicator.swift
+++ b/NohanaImagePicker/AlbumListEmptyIndicator.swift
@@ -23,22 +23,22 @@ class AlbumListEmptyIndicator: UILabel {
         centerStyle.alignment = NSTextAlignment.center
 
         let messageAttributes = [
-            NSForegroundColorAttributeName : config.color.empty ?? UIColor(red: 0x88/0xff, green: 0x88/0xff, blue: 0x88/0xff, alpha: 1),
-            NSFontAttributeName : UIFont.systemFont(ofSize: 26),
-            NSParagraphStyleAttributeName : centerStyle
+            NSAttributedStringKey.foregroundColor : config.color.empty ?? UIColor(red: 0x88/0xff, green: 0x88/0xff, blue: 0x88/0xff, alpha: 1),
+            NSAttributedStringKey.font : UIFont.systemFont(ofSize: 26),
+            NSAttributedStringKey.paragraphStyle : centerStyle
         ]
         let messageText = NSAttributedString(string: message, attributes: messageAttributes)
 
         let descriptionAttributes = [
-            NSForegroundColorAttributeName : config.color.empty ?? UIColor(red: 0x88/0xff, green: 0x88/0xff, blue: 0x88/0xff, alpha: 1),
-            NSFontAttributeName : UIFont.systemFont(ofSize: 14),
-            NSParagraphStyleAttributeName : centerStyle
+            NSAttributedStringKey.foregroundColor : config.color.empty ?? UIColor(red: 0x88/0xff, green: 0x88/0xff, blue: 0x88/0xff, alpha: 1),
+            NSAttributedStringKey.font : UIFont.systemFont(ofSize: 14),
+            NSAttributedStringKey.paragraphStyle : centerStyle
         ]
         let descriptionText = NSAttributedString(string: description, attributes: descriptionAttributes)
 
         let attributedText = NSMutableAttributedString()
         attributedText.append(messageText)
-        attributedText.append(NSAttributedString(string: "\n\n", attributes: [NSFontAttributeName : UIFont.systemFont(ofSize: 6)]))
+        attributedText.append(NSAttributedString(string: "\n\n", attributes: [NSAttributedStringKey.font : UIFont.systemFont(ofSize: 6)]))
         attributedText.append(descriptionText)
 
         self.numberOfLines = 0
diff --git a/NohanaImagePicker/AlbumListViewController.swift b/NohanaImagePicker/AlbumListViewController.swift
index c1e8ff2..32207f1 100644
--- a/NohanaImagePicker/AlbumListViewController.swift
+++ b/NohanaImagePicker/AlbumListViewController.swift
@@ -261,7 +261,7 @@ extension UIViewController {
 
         let infoButton = UIBarButtonItem(title: "", style: .plain, target: nil, action: nil)
         infoButton.isEnabled = false
-        infoButton.setTitleTextAttributes([NSFontAttributeName: UIFont.systemFont(ofSize: 14), NSForegroundColorAttributeName: UIColor.black], for: UIControlState())
+        infoButton.setTitleTextAttributes([NSAttributedStringKey.font: UIFont.systemFont(ofSize: 14), NSAttributedStringKey.foregroundColor: UIColor.black], for: UIControlState())
         self.toolbarItems = [leftSpace, infoButton, rightSpace]
     }
 
@@ -292,14 +292,14 @@ extension UIViewController {
         NotificationCenter.default.addObserver(self, selector: #selector(AlbumListViewController.didDropPhotoKitAsset(_:)), name:  NotificationInfo.Asset.PhotoKit.didDrop, object: nil)
     }
 
-    func didPickPhotoKitAsset(_ notification: Notification) {
+    @objc func didPickPhotoKitAsset(_ notification: Notification) {
         guard let picker = notification.object as? NohanaImagePickerController else {
             return
         }
         setToolbarTitle(picker)
     }
 
-    func didDropPhotoKitAsset(_ notification: Notification) {
+    @objc func didDropPhotoKitAsset(_ notification: Notification) {
         guard let picker = notification.object as? NohanaImagePickerController else {
             return
         }
diff --git a/NohanaImagePicker/AssetDetailCell.swift b/NohanaImagePicker/AssetDetailCell.swift
index 48acc54..c8804f8 100644
--- a/NohanaImagePicker/AssetDetailCell.swift
+++ b/NohanaImagePicker/AssetDetailCell.swift
@@ -50,7 +50,7 @@ class AssetDetailCell: UICollectionViewCell, UIScrollViewDelegate {
 
     // MARK: - Zoom
 
-    func didDoubleTap(_ sender: UITapGestureRecognizer) {
+    @objc func didDoubleTap(_ sender: UITapGestureRecognizer) {
         if scrollView.zoomScale < scrollView.maximumZoomScale {
             let center = sender.location(in: imageView)
             scrollView.zoom(to: zoomRect(center), animated: true)
diff --git a/NohanaImagePicker/ContractingAnimationController.swift b/NohanaImagePicker/ContractingAnimationController.swift
index 19af456..28dd324 100644
--- a/NohanaImagePicker/ContractingAnimationController.swift
+++ b/NohanaImagePicker/ContractingAnimationController.swift
@@ -78,7 +78,7 @@ class ContractingAnimationController: NSObject, UIViewControllerAnimatedTransiti
             withDuration: transitionDuration(using: transitionContext),
             delay: 0,
             options: UIViewAnimationOptions(),
-            animations: { _ in
+            animations: { 
                 toVC.view.alpha = 1
                 contractingImageView.frame = Size.contractingAnimationToCellRect(toVC, toCell: toCell)
             }) { _  in