diff --git a/Source/AppleStorage/Implement/CoreDataArrayStorage.swift b/Source/AppleStorage/Implement/CoreDataArrayStorage.swift
index 7ceafd7..25bc00f 100644
--- a/Source/AppleStorage/Implement/CoreDataArrayStorage.swift
+++ b/Source/AppleStorage/Implement/CoreDataArrayStorage.swift
@@ -12,9 +12,11 @@ import SabySafe
 import SabySize
 import SabyJSON
 
+private let STORAGE_VERSION = "Version1"
+
 public final class CoreDataArrayStorage<Value: Codable & KeyIdentifiable>: ArrayStorage {
     typealias Context = NSManagedObjectContext
-    typealias Item = SabyCoreDataArrayStorageItem
+    typealias Item = SabyCoreDataArrayStorageItemVersion1
     
     let entity: NSEntityDescription
     
@@ -24,7 +26,7 @@ public final class CoreDataArrayStorage<Value: Codable & KeyIdentifiable>: Array
     let encoder = JSONEncoder.acceptingNonConfirmingFloat()
     let decoder = JSONDecoder.acceptingNonConfirmingFloat()
     
-    public init(directoryURL: URL, fileName: String, migration: @escaping () -> Promise<Void, Error>) {
+    public init(directoryURL: URL, storageName: String, migration: @escaping () -> Promise<Void, Error>) {
         let schema = SabyCoreDataArrayStorageSchema()
         
         self.entity = schema.entity
@@ -32,7 +34,7 @@ public final class CoreDataArrayStorage<Value: Codable & KeyIdentifiable>: Array
         self.contextLoad = {
             Context.load(
                 directoryURL: directoryURL,
-                fileName: fileName,
+                storageName: storageName,
                 migration: migration,
                 model: schema.model
             )
@@ -50,7 +52,7 @@ extension CoreDataArrayStorage {
             let request = self.createAnyRequest(key: key)
             try context.executeDelete(request)
 
-            let item = SabyCoreDataArrayStorageItem(
+            let item = SabyCoreDataArrayStorageItemVersion1(
                 entity: self.entity,
                 insertInto: context
             )
@@ -70,7 +72,7 @@ extension CoreDataArrayStorage {
             try context.executeDelete(request)
             
             for value in values {
-                let item = SabyCoreDataArrayStorageItem(
+                let item = SabyCoreDataArrayStorageItemVersion1(
                     entity: self.entity,
                     insertInto: context
                 )
@@ -195,7 +197,7 @@ extension CoreDataArrayStorage {
     }
     
     fileprivate func createSizeRequest() -> NSFetchRequest<NSDictionary> {
-        let byteExpression = NSExpression(forKeyPath: \SabyCoreDataArrayStorageItem.byte)
+        let byteExpression = NSExpression(forKeyPath: \SabyCoreDataArrayStorageItemVersion1.byte)
         let sumExpression = NSExpression(forFunction: "sum:", arguments: [byteExpression])
         let sumDescription = NSExpressionDescription()
         sumDescription.expression = sumExpression
@@ -335,7 +337,7 @@ extension NSManagedObjectContext {
 extension NSManagedObjectContext {
     static func load(
         directoryURL: URL,
-        fileName: String,
+        storageName: String,
         migration: @escaping () -> Promise<Void, Error>,
         model: NSManagedObjectModel
     ) -> Promise<NSManagedObjectContext, Error> {
@@ -353,10 +355,10 @@ extension NSManagedObjectContext {
                 )
             }
             
-            let url = directoryURL.appendingPathComponent(fileName)
+            let url = directoryURL.appendingPathComponent(storageName).appendingPathExtension(STORAGE_VERSION)
 
             let container = NSPersistentContainer(
-                name: fileName,
+                name: storageName,
                 managedObjectModel: model
             )
             let storeDescription = NSPersistentStoreDescription(url: url)
@@ -380,8 +382,9 @@ public enum CoreDataArrayStorageError: Error {
     case requestResultNotFound
 }
 
-@objc(SabyCoreDataArrayStorageItem)
-final class SabyCoreDataArrayStorageItem: NSManagedObject {
+// Must not be modified. Write ItemVersion2 and write migration logic instead.
+@objc(SabyCoreDataArrayStorageItemVersion1)
+final class SabyCoreDataArrayStorageItemVersion1: NSManagedObject {
     @NSManaged var key: UUID
     @NSManaged var data: Data
     @NSManaged var date: Date
@@ -426,8 +429,8 @@ final class SabyCoreDataArrayStorageSchema {
         }
         
         let itemEntity = NSEntityDescription()
-        itemEntity.name = String(describing: SabyCoreDataArrayStorageItem.self)
-        itemEntity.managedObjectClassName = String(describing: SabyCoreDataArrayStorageItem.self)
+        itemEntity.name = String(describing: SabyCoreDataArrayStorageItemVersion1.self)
+        itemEntity.managedObjectClassName = String(describing: SabyCoreDataArrayStorageItemVersion1.self)
         itemEntity.properties = [
             keyAttribute,
             dataAttribute,
diff --git a/Source/AppleStorage/Implement/FileArrayStorage.swift b/Source/AppleStorage/Implement/FileArrayStorage.swift
index f9c28ba..895f4bc 100644
--- a/Source/AppleStorage/Implement/FileArrayStorage.swift
+++ b/Source/AppleStorage/Implement/FileArrayStorage.swift
@@ -10,9 +10,11 @@ import SabyConcurrency
 import SabySize
 import SabyJSON
 
+private let STORAGE_VERSION = "Version1"
+
 public final class FileArrayStorage<Value: Codable & KeyIdentifiable>: ArrayStorage {
     typealias Context = FileArrayStorageContext
-    typealias Item = FileArrayStorageItem
+    typealias Item = FileArrayStorageItemVersion1
     
     let fileLock = Lock()
     
@@ -21,11 +23,11 @@ public final class FileArrayStorage<Value: Codable & KeyIdentifiable>: ArrayStor
     
     let encoder = JSONEncoder.acceptingNonConfirmingFloat()
 
-    public init(directoryURL: URL, fileName: String, migration: @escaping () -> Promise<Void, Error>) {
+    public init(directoryURL: URL, storageName: String, migration: @escaping () -> Promise<Void, Error>) {
         self.contextLoad = {
             Context.load(
                 directoryURL: directoryURL,
-                fileName: fileName,
+                storageName: storageName,
                 migration: migration
             )
         }
@@ -191,11 +193,11 @@ extension FileArrayStorage {
 
 struct FileArrayStorageContext<Value: Codable> {
     let url: URL
-    let items: Atomic<[FileArrayStorageItem<Value>]>
+    let items: Atomic<[FileArrayStorageItemVersion1<Value>]>
     
     private init(
         url: URL,
-        items: Atomic<[FileArrayStorageItem<Value>]>
+        items: Atomic<[FileArrayStorageItemVersion1<Value>]>
     ) {
         self.url = url
         self.items = items
@@ -203,7 +205,7 @@ struct FileArrayStorageContext<Value: Codable> {
     
     static func load(
         directoryURL: URL,
-        fileName: String,
+        storageName: String,
         migration: @escaping () -> Promise<Void, Error>
     ) -> Promise<FileArrayStorageContext, Error> {
         migration().then {
@@ -221,7 +223,7 @@ struct FileArrayStorageContext<Value: Codable> {
                 )
             }
             
-            let url = directoryURL.appendingPathComponent(fileName)
+            let url = directoryURL.appendingPathComponent(storageName).appendingPathExtension(STORAGE_VERSION)
             if !fileManager.fileExists(atPath: url.path) {
                 return FileArrayStorageContext(
                     url: url,
@@ -232,7 +234,7 @@ struct FileArrayStorageContext<Value: Codable> {
             guard
                 let data = try? Data(contentsOf: url),
                 let items = try? decoder.decode(
-                    [FileArrayStorageItem<Value>].self,
+                    [FileArrayStorageItemVersion1<Value>].self,
                     from: data
                 )
             else {
@@ -254,7 +256,8 @@ public enum FileArrayStorageError: Error {
     case libraryDirectoryNotFound
 }
 
-struct FileArrayStorageItem<Value: Codable>: Codable {
+// Must not be modified. Write ItemVersion2 and write migration logic instead.
+struct FileArrayStorageItemVersion1<Value: Codable>: Codable {
     let key: UUID
     let value: Value
     let date: Date
diff --git a/Source/AppleStorage/Implement/FileDictionaryStorage.swift b/Source/AppleStorage/Implement/FileDictionaryStorage.swift
index f4e2a69..cb170ce 100644
--- a/Source/AppleStorage/Implement/FileDictionaryStorage.swift
+++ b/Source/AppleStorage/Implement/FileDictionaryStorage.swift
@@ -9,6 +9,8 @@ import Foundation
 import SabyConcurrency
 import SabyJSON
 
+private let STORAGE_VERSION = "Version1"
+
 public final class FileDictionaryStorage<
     Key: Hashable & Codable,
     Value: Codable
@@ -22,11 +24,11 @@ public final class FileDictionaryStorage<
     
     let encoder = JSONEncoder.acceptingNonConfirmingFloat()
 
-    public init(directoryURL: URL, fileName: String, migration: @escaping () -> Promise<Void, Error>) {
+    public init(directoryURL: URL, storageName: String, migration: @escaping () -> Promise<Void, Error>) {
         self.contextLoad = {
             Context.load(
                 directoryURL: directoryURL,
-                fileName: fileName,
+                storageName: storageName,
                 migration: migration
             )
         }
@@ -107,16 +109,16 @@ extension FileDictionaryStorage {
 
 struct FileDictionaryStorageContext<Key: Hashable & Codable, Value: Codable> {
     let url: URL
-    let values: Atomic<[Key: Value]>
+    let values: Atomic<FileDictionaryStorageItemVersion1<Key, Value>>
     
-    private init(url: URL, values: Atomic<[Key: Value]>) {
+    private init(url: URL, values: Atomic<FileDictionaryStorageItemVersion1<Key, Value>>) {
         self.url = url
         self.values = values
     }
     
     static func load(
         directoryURL: URL,
-        fileName: String,
+        storageName: String,
         migration: @escaping () -> Promise<Void, Error>
     ) -> Promise<FileDictionaryStorageContext, Error> {
         migration().then {
@@ -134,7 +136,7 @@ struct FileDictionaryStorageContext<Key: Hashable & Codable, Value: Codable> {
                 )
             }
             
-            let url = directoryURL.appendingPathComponent(fileName)
+            let url = directoryURL.appendingPathComponent(storageName).appendingPathExtension(STORAGE_VERSION)
             if !fileManager.fileExists(atPath: url.path) {
                 return FileDictionaryStorageContext(
                     url: url,
@@ -145,7 +147,7 @@ struct FileDictionaryStorageContext<Key: Hashable & Codable, Value: Codable> {
             guard
                 let data = try? Data(contentsOf: url),
                 let values = try? decoder.decode(
-                    [Key: Value].self,
+                    FileDictionaryStorageItemVersion1<Key, Value>.self,
                     from: data
                 )
             else {
@@ -162,3 +164,6 @@ struct FileDictionaryStorageContext<Key: Hashable & Codable, Value: Codable> {
         }
     }
 }
+
+// Must not be modified. Write ItemVersion2 and write migration logic instead.
+typealias FileDictionaryStorageItemVersion1<Key: Hashable & Codable, Value: Codable> = [Key: Value]
diff --git a/Source/AppleStorage/Implement/FileValueStorage.swift b/Source/AppleStorage/Implement/FileValueStorage.swift
index d73b335..23f4ac3 100644
--- a/Source/AppleStorage/Implement/FileValueStorage.swift
+++ b/Source/AppleStorage/Implement/FileValueStorage.swift
@@ -10,6 +10,8 @@ import SabySafe
 import SabyConcurrency
 import SabyJSON
 
+private let STORAGE_VERSION = "Version1"
+
 public final class FileValueStorage<Value: Codable>: ValueStorage {
     typealias Context = FileValueStorageContext
     
@@ -20,11 +22,11 @@ public final class FileValueStorage<Value: Codable>: ValueStorage {
     
     let encoder = JSONEncoder.acceptingNonConfirmingFloat()
 
-    public init(directoryURL: URL, fileName: String, migration: @escaping () -> Promise<Void, Error>) {
+    public init(directoryURL: URL, storageName: String, migration: @escaping () -> Promise<Void, Error>) {
         self.contextLoad = {
             Context.load(
                 directoryURL: directoryURL,
-                fileName: fileName,
+                storageName: storageName,
                 migration: migration
             )
         }
@@ -91,16 +93,16 @@ extension FileValueStorage {
 
 struct FileValueStorageContext<Value: Codable> {
     let url: URL
-    let value: Atomic<Value?>
+    let value: Atomic<FileValueStorageItemVersion1<Value>?>
     
-    private init(url: URL, value: Atomic<Value?>) {
+    private init(url: URL, value: Atomic<FileValueStorageItemVersion1<Value>?>) {
         self.url = url
         self.value = value
     }
     
     static func load(
         directoryURL: URL,
-        fileName: String,
+        storageName: String,
         migration: @escaping () -> Promise<Void, Error>
     ) -> Promise<FileValueStorageContext, Error> {
         migration().then {
@@ -118,7 +120,7 @@ struct FileValueStorageContext<Value: Codable> {
                 )
             }
             
-            let url = directoryURL.appendingPathComponent(fileName)
+            let url = directoryURL.appendingPathComponent(storageName).appendingPathExtension(STORAGE_VERSION)
             if !fileManager.fileExists(atPath: url.path) {
                 return FileValueStorageContext(
                     url: url,
@@ -129,7 +131,7 @@ struct FileValueStorageContext<Value: Codable> {
             guard
                 let data = try? Data(contentsOf: url),
                 let value = try? decoder.decode(
-                    Value?.self,
+                    FileValueStorageItemVersion1<Value>?.self,
                     from: data
                 )
             else {
@@ -146,3 +148,6 @@ struct FileValueStorageContext<Value: Codable> {
         }
     }
 }
+
+// Must not be modified. Write ItemVersion2 and write migration logic instead.
+typealias FileValueStorageItemVersion1<Value: Codable> = Value
diff --git a/Source/AppleStorage/Storage.swift b/Source/AppleStorage/Storage.swift
index 9d55eff..65b53d1 100644
--- a/Source/AppleStorage/Storage.swift
+++ b/Source/AppleStorage/Storage.swift
@@ -9,17 +9,17 @@ import Foundation
 import SabyConcurrency
 
 public protocol Storage {
-    /// ``init(directoryURL:fileName:migration:)``
+    /// ``init(directoryURL:storageName:migration:)``
     /// execute migration and then create or load preference from
-    /// `{Directory url}/{File name}` path.
-    init(directoryURL: URL, fileName: String, migration: @escaping () -> Promise<Void, Error>)
+    /// `{Directory url}/{Storage name}/{Version name}` path.
+    init(directoryURL: URL, storageName: String, migration: @escaping () -> Promise<Void, Error>)
 }
 
 extension Storage {
-    /// ``init(directoryName:fileName:)`` create or load storage from
-    /// `{Directory url}/{File name}` path.
-    public init(directoryURL: URL, fileName: String) {
-        self.init(directoryURL: directoryURL, fileName: fileName, migration: { .resolved(()) })
+    /// ``init(directoryName:storageName:)`` create or load storage from
+    /// `{Directory url}/{Storage name}/{Version name}` path.
+    public init(directoryURL: URL, storageName: String) {
+        self.init(directoryURL: directoryURL, storageName: storageName, migration: { .resolved(()) })
     }
 }
 
diff --git a/Test/AppleStorage/Implement/CoreDataArrayStorageTest.swift b/Test/AppleStorage/Implement/CoreDataArrayStorageTest.swift
index 9f9374c..7e74738 100644
--- a/Test/AppleStorage/Implement/CoreDataArrayStorageTest.swift
+++ b/Test/AppleStorage/Implement/CoreDataArrayStorageTest.swift
@@ -20,7 +20,7 @@ class CoreDataArrayStorageTest: XCTestCase {
     var encoder: JSONEncoder!
     
     override func setUpWithError() throws {
-        storage = CoreDataArrayStorage(directoryURL: FileManager.default.temporaryDirectory, fileName: "\(UUID())")
+        storage = CoreDataArrayStorage(directoryURL: FileManager.default.temporaryDirectory, storageName: "\(UUID())")
         encoder = JSONEncoder()
     }
     
diff --git a/Test/AppleStorage/Implement/FileArrayStorageTest.swift b/Test/AppleStorage/Implement/FileArrayStorageTest.swift
index 1c624bd..03c4639 100644
--- a/Test/AppleStorage/Implement/FileArrayStorageTest.swift
+++ b/Test/AppleStorage/Implement/FileArrayStorageTest.swift
@@ -17,7 +17,7 @@ final class FileArrayStorageTest: XCTestCase {
     fileprivate var storage: FileArrayStorage<DummyItem>!
     fileprivate var encoder: JSONEncoder!
     fileprivate let directoryURL = FileManager.default.temporaryDirectory
-    fileprivate var fileName: String!
+    fileprivate var storageName: String!
     
     private struct TestItemGroup {
         private static let testCount = 100
@@ -37,16 +37,16 @@ final class FileArrayStorageTest: XCTestCase {
     }
     
     override func setUpWithError() throws {
-        fileName = UUID().uuidString
+        storageName = UUID().uuidString
         storage = FileArrayStorage<DummyItem>(
             directoryURL: directoryURL,
-            fileName: fileName
+            storageName: storageName
         )
         encoder = JSONEncoder()
     }
     
     override func tearDownWithError() throws {
-        let fileURL = directoryURL.appendingPathComponent(fileName)
+        let fileURL = directoryURL.appendingPathComponent(storageName)
         
         if FileManager.default.fileExists(atPath: fileURL.absoluteString) {
             try FileManager.default.removeItem(at: fileURL)
diff --git a/Test/AppleStorage/Implement/FileDictionaryStorageTest.swift b/Test/AppleStorage/Implement/FileDictionaryStorageTest.swift
index 6331651..d11381d 100644
--- a/Test/AppleStorage/Implement/FileDictionaryStorageTest.swift
+++ b/Test/AppleStorage/Implement/FileDictionaryStorageTest.swift
@@ -17,7 +17,7 @@ final class FileDictionaryStorageTest: XCTestCase {
     fileprivate let testCount = 500
     fileprivate var storage: FileDictionaryStorage<String, DummyItem>!
     fileprivate let directoryURL = FileManager.default.temporaryDirectory
-    fileprivate var fileName: String!
+    fileprivate var storageName: String!
     
     fileprivate var testObjects: [(String, DummyItem)] {
         var result: [(String, DummyItem)] = []
@@ -29,15 +29,15 @@ final class FileDictionaryStorageTest: XCTestCase {
     }
     
     override func setUpWithError() throws {
-        fileName = UUID().uuidString
+        storageName = UUID().uuidString
         storage = FileDictionaryStorage<String, DummyItem>(
             directoryURL: directoryURL,
-            fileName: fileName
+            storageName: storageName
         )
     }
     
     override func tearDownWithError() throws {
-        let fileURL = directoryURL.appendingPathComponent(fileName)
+        let fileURL = directoryURL.appendingPathComponent(storageName)
         
         if FileManager.default.fileExists(atPath: fileURL.absoluteString) {
             try FileManager.default.removeItem(at: fileURL)
diff --git a/Test/AppleStorage/Implement/FileValueStorageTest.swift b/Test/AppleStorage/Implement/FileValueStorageTest.swift
index 26614e5..a2296bb 100644
--- a/Test/AppleStorage/Implement/FileValueStorageTest.swift
+++ b/Test/AppleStorage/Implement/FileValueStorageTest.swift
@@ -17,7 +17,7 @@ final class FileValueStorageTest: XCTestCase {
     fileprivate let testCount = 500
     fileprivate var storage: FileValueStorage<DummyItem>!
     fileprivate let directoryURL = FileManager.default.temporaryDirectory
-    fileprivate var fileName: String!
+    fileprivate var storageName: String!
     
     fileprivate var testObjects: [DummyItem] {
         var result: [DummyItem] = []
@@ -29,15 +29,15 @@ final class FileValueStorageTest: XCTestCase {
     }
     
     override func setUpWithError() throws {
-        fileName = UUID().uuidString
+        storageName = UUID().uuidString
         storage = FileValueStorage<DummyItem>(
             directoryURL: directoryURL,
-            fileName: fileName
+            storageName: storageName
         )
     }
     
     override func tearDownWithError() throws {
-        let fileURL = directoryURL.appendingPathComponent(fileName)
+        let fileURL = directoryURL.appendingPathComponent(storageName)
         
         if FileManager.default.fileExists(atPath: fileURL.absoluteString) {
             try FileManager.default.removeItem(at: fileURL)