diff --git a/Sources/Defaults/Migration/Migration+Defaults.swift b/Sources/Defaults/Migration/Migration+Defaults.swift
deleted file mode 100644
index d87ebdb..0000000
--- a/Sources/Defaults/Migration/Migration+Defaults.swift
+++ /dev/null
@@ -1,46 +0,0 @@
-import Foundation
-
-extension Defaults {
-	public enum Version: Int {
-		case v5 = 5
-	}
-
-	/**
-	Migrate the given key's value from JSON string to `Value`.
-
-	```swift
-	extension Defaults.Keys {
-		static let array = Key<Set<String>?>("array")
-	}
-
-	Defaults.migrate(.array, to: .v5)
-	```
-	*/
-	public static func migrate<Value: Serializable & Codable>(_ keys: Key<Value>..., to version: Version) {
-		migrate(keys, to: version)
-	}
-
-	public static func migrate<Value: NativeType>(_ keys: Key<Value>..., to version: Version) {
-		migrate(keys, to: version)
-	}
-
-	public static func migrate<Value: Serializable & Codable>(_ keys: [Key<Value>], to version: Version) {
-		switch version {
-		case .v5:
-			for key in keys {
-				let suite = key.suite
-				suite.migrateCodableToNative(forKey: key.name, of: Value.self)
-			}
-		}
-	}
-
-	public static func migrate<Value: NativeType>(_ keys: [Key<Value>], to version: Version) {
-		switch version {
-		case .v5:
-			for key in keys {
-				let suite = key.suite
-				suite.migrateCodableToNative(forKey: key.name, of: Value.self)
-			}
-		}
-	}
-}
diff --git a/Sources/Defaults/Migration/v5/Migration+Extensions.swift b/Sources/Defaults/Migration/v5/Migration+Extensions.swift
deleted file mode 100644
index d9243d4..0000000
--- a/Sources/Defaults/Migration/v5/Migration+Extensions.swift
+++ /dev/null
@@ -1,235 +0,0 @@
-import Foundation
-import CoreGraphics
-
-extension Defaults {
-	public typealias NativeType = _DefaultsNativeType
-	public typealias CodableType = _DefaultsCodableType
-}
-
-extension Data: Defaults.NativeType {
-	public typealias CodableForm = Self
-}
-
-extension Data: Defaults.CodableType {
-	public typealias NativeForm = Self
-
-	public func toNative() -> Self { self }
-}
-
-extension Date: Defaults.NativeType {
-	public typealias CodableForm = Self
-}
-
-extension Date: Defaults.CodableType {
-	public typealias NativeForm = Self
-
-	public func toNative() -> Self { self }
-}
-
-extension Bool: Defaults.NativeType {
-	public typealias CodableForm = Self
-}
-
-extension Bool: Defaults.CodableType {
-	public typealias NativeForm = Self
-
-	public func toNative() -> Self { self }
-}
-
-extension Int: Defaults.NativeType {
-	public typealias CodableForm = Self
-}
-
-extension Int: Defaults.CodableType {
-	public typealias NativeForm = Self
-
-	public func toNative() -> Self { self }
-}
-
-extension UInt: Defaults.NativeType {
-	public typealias CodableForm = Self
-}
-
-extension UInt: Defaults.CodableType {
-	public typealias NativeForm = Self
-
-	public func toNative() -> Self { self }
-}
-
-extension Double: Defaults.NativeType {
-	public typealias CodableForm = Self
-}
-
-extension Double: Defaults.CodableType {
-	public typealias NativeForm = Self
-
-	public func toNative() -> Self { self }
-}
-
-extension Float: Defaults.NativeType {
-	public typealias CodableForm = Self
-}
-
-extension Float: Defaults.CodableType {
-	public typealias NativeForm = Self
-
-	public func toNative() -> Self { self }
-}
-
-extension String: Defaults.NativeType {
-	public typealias CodableForm = Self
-}
-
-extension String: Defaults.CodableType {
-	public typealias NativeForm = Self
-
-	public func toNative() -> Self { self }
-}
-
-extension CGFloat: Defaults.NativeType {
-	public typealias CodableForm = Self
-}
-
-extension CGFloat: Defaults.CodableType {
-	public typealias NativeForm = Self
-
-	public func toNative() -> Self { self }
-}
-
-extension Int8: Defaults.NativeType {
-	public typealias CodableForm = Self
-}
-
-extension Int8: Defaults.CodableType {
-	public typealias NativeForm = Self
-
-	public func toNative() -> Self { self }
-}
-
-extension UInt8: Defaults.NativeType {
-	public typealias CodableForm = Self
-}
-
-extension UInt8: Defaults.CodableType {
-	public typealias NativeForm = Self
-
-	public func toNative() -> Self { self }
-}
-
-extension Int16: Defaults.NativeType {
-	public typealias CodableForm = Self
-}
-
-extension Int16: Defaults.CodableType {
-	public typealias NativeForm = Self
-
-	public func toNative() -> Self { self }
-}
-
-extension UInt16: Defaults.NativeType {
-	public typealias CodableForm = Self
-}
-
-extension UInt16: Defaults.CodableType {
-	public typealias NativeForm = Self
-
-	public func toNative() -> Self { self }
-}
-
-extension Int32: Defaults.NativeType {
-	public typealias CodableForm = Self
-}
-
-extension Int32: Defaults.CodableType {
-	public typealias NativeForm = Self
-
-	public func toNative() -> Self { self }
-}
-
-extension UInt32: Defaults.NativeType {
-	public typealias CodableForm = Self
-}
-
-extension UInt32: Defaults.CodableType {
-	public typealias NativeForm = Self
-
-	public func toNative() -> Self { self }
-}
-
-extension Int64: Defaults.NativeType {
-	public typealias CodableForm = Self
-}
-
-extension Int64: Defaults.CodableType {
-	public typealias NativeForm = Self
-
-	public func toNative() -> Self { self }
-}
-
-extension UInt64: Defaults.NativeType {
-	public typealias CodableForm = Self
-}
-
-extension UInt64: Defaults.CodableType {
-	public typealias NativeForm = Self
-
-	public func toNative() -> Self { self }
-}
-
-extension URL: Defaults.NativeType {
-	public typealias CodableForm = Self
-}
-
-extension URL: Defaults.CodableType {
-	public typealias NativeForm = Self
-
-	public func toNative() -> Self { self }
-}
-
-extension Optional: Defaults.NativeType where Wrapped: Defaults.NativeType {
-	public typealias CodableForm = Wrapped.CodableForm
-}
-
-extension Defaults.CollectionSerializable where Self: Defaults.NativeType, Element: Defaults.NativeType {
-	public typealias CodableForm = [Element.CodableForm]
-}
-
-extension Defaults.SetAlgebraSerializable where Self: Defaults.NativeType, Element: Defaults.NativeType {
-	public typealias CodableForm = [Element.CodableForm]
-}
-
-extension Defaults.CodableType where Self: RawRepresentable<NativeForm.RawValue>, NativeForm: RawRepresentable {
-	public func toNative() -> NativeForm {
-		NativeForm(rawValue: rawValue)!
-	}
-}
-
-extension Set: Defaults.NativeType where Element: Defaults.NativeType {
-	public typealias CodableForm = [Element.CodableForm]
-}
-
-extension Array: Defaults.NativeType where Element: Defaults.NativeType {
-	public typealias CodableForm = [Element.CodableForm]
-}
-
-extension Array: Defaults.CodableType where Element: Defaults.CodableType {
-	public typealias NativeForm = [Element.NativeForm]
-
-	public func toNative() -> NativeForm {
-		map { $0.toNative() }
-	}
-}
-
-extension Dictionary: Defaults.NativeType where Key: LosslessStringConvertible & Hashable, Value: Defaults.NativeType {
-	public typealias CodableForm = [String: Value.CodableForm]
-}
-
-extension Dictionary: Defaults.CodableType where Key == String, Value: Defaults.CodableType {
-	public typealias NativeForm = [String: Value.NativeForm]
-
-	public func toNative() -> NativeForm {
-		reduce(into: NativeForm()) { memo, tuple in
-			memo[tuple.key] = tuple.value.toNative()
-		}
-	}
-}
diff --git a/Sources/Defaults/Migration/v5/Migration+Protocol.swift b/Sources/Defaults/Migration/v5/Migration+Protocol.swift
deleted file mode 100644
index a68c422..0000000
--- a/Sources/Defaults/Migration/v5/Migration+Protocol.swift
+++ /dev/null
@@ -1,61 +0,0 @@
-import Foundation
-
-/**
-Only exists for migration.
-
-Represents the type after migration and its protocol should conform to `Defaults.Serializable`.
-
-It should have an associated type name `CodableForm` where its protocol conform to `Codable`.
-
-So we can convert the JSON string into a `NativeType` like this:
-
-```swift
-guard
-	let jsonData = string?.data(using: .utf8),
-	let codable = try? JSONDecoder().decode(NativeType.CodableForm.self, from: jsonData)
-else {
-	return nil
-}
-
-return codable.toNative()
-```
-*/
-public protocol _DefaultsNativeType: Defaults.Serializable {
-	associatedtype CodableForm: Defaults.CodableType
-}
-
-/**
-Only exists for migration.
-
-Represents the type before migration an its protocol should conform to `Codable`.
-
-The main purposed of `CodableType` is trying to infer the `Codable` type to do `JSONDecoder().decode`. It should have an associated type name `NativeForm` which is the type we want it to store in `UserDefaults`. nd it also have a `toNative()` function to convert itself into `NativeForm`.
-
-```swift
-struct User {
-	username: String
-	password: String
-}
-
-struct CodableUser: Codable {
-	username: String
-	password: String
-}
-
-extension User: Defaults.NativeType {
-	typealias CodableForm = CodableUser
-}
-
-extension CodableUser: Defaults.CodableType {
-	typealias NativeForm = User
-
-	func toNative() -> NativeForm {
-		User(username: self.username, password: self.password)
-	}
-}
-```
-*/
-public protocol _DefaultsCodableType: Codable {
-	associatedtype NativeForm: Defaults.NativeType
-	func toNative() -> NativeForm
-}
diff --git a/Sources/Defaults/Migration/v5/Migration+UserDefaults.swift b/Sources/Defaults/Migration/v5/Migration+UserDefaults.swift
deleted file mode 100644
index feb7c2b..0000000
--- a/Sources/Defaults/Migration/v5/Migration+UserDefaults.swift
+++ /dev/null
@@ -1,48 +0,0 @@
-import Foundation
-
-extension UserDefaults {
-	func migrateCodableToNative<Value: Defaults.Serializable & Codable>(forKey key: String, of type: Value.Type) {
-		guard
-			let jsonData = string(forKey: key)?.data(using: .utf8),
-			let codable = try? JSONDecoder().decode(Value.self, from: jsonData)
-		else {
-			return
-		}
-
-		_set(key, to: codable)
-	}
-
-	/**
-	Get a JSON string in `UserDefaults` and decode it into its `NativeForm`.
-
-	How does it work?
-
-	1. If `Value` is  `[String]`, `Value.CodableForm` will covert into `[String].CodableForm`.
-
-	```swift
-	JSONDecoder().decode([String].CodableForm.self, from: jsonData)
-	```
-
-	2. If `Array` conforms to `NativeType`, its `CodableForm` is `[Element.CodableForm]` and `Element` is `String`.
-
-	```swift
-	JSONDecoder().decode([String.CodableForm].self, from: jsonData)
-	```
-
-	3. `String`'s `CodableForm` is `self`,  because `String` is `Codable`.
-
-	```swift
-	JSONDecoder().decode([String].self, from: jsonData)
-	```
-	*/
-	func migrateCodableToNative<Value: Defaults.NativeType>(forKey key: String, of type: Value.Type) {
-		guard
-			let jsonData = string(forKey: key)?.data(using: .utf8),
-			let codable = try? JSONDecoder().decode(Value.CodableForm.self, from: jsonData)
-		else {
-			return
-		}
-
-		_set(key, to: codable.toNative())
-	}
-}
diff --git a/Tests/DefaultsTests/DefaultsMigrationTests.swift b/Tests/DefaultsTests/DefaultsMigrationTests.swift
deleted file mode 100644
index 5f30efa..0000000
--- a/Tests/DefaultsTests/DefaultsMigrationTests.swift
+++ /dev/null
@@ -1,1167 +0,0 @@
-import Defaults
-import Foundation
-import XCTest
-
-// Create an unique ID to test whether `LosslessStringConvertible` works.
-private struct UniqueID: LosslessStringConvertible, Hashable {
-	var id: Int64
-
-	var description: String {
-		"\(id)"
-	}
-
-	init(id: Int64) {
-		self.id = id
-	}
-
-	init?(_ description: String) {
-		self.init(id: Int64(description) ?? 0)
-	}
-}
-
-private struct TimeZone: Hashable {
-	var id: String
-	var name: String
-}
-
-extension TimeZone: Defaults.NativeType {
-	/**
-	Associated `CodableForm` to `CodableTimeZone`.
-	*/
-	typealias CodableForm = CodableTimeZone
-
-	static let bridge = TimeZoneBridge()
-}
-
-private struct CodableTimeZone {
-	var id: String
-	var name: String
-}
-
-extension CodableTimeZone: Defaults.CodableType {
-	/**
-	Convert from `Codable` to `Native`.
-	*/
-	func toNative() -> TimeZone {
-		TimeZone(id: id, name: name)
-	}
-}
-
-private struct TimeZoneBridge: Defaults.Bridge {
-	typealias Value = TimeZone
-	typealias Serializable = [String: Any]
-
-	func serialize(_ value: TimeZone?) -> Serializable? {
-		guard let value else {
-			return nil
-		}
-
-		return ["id": value.id, "name": value.name]
-	}
-
-	func deserialize(_ object: Serializable?) -> TimeZone? {
-		guard
-			let object,
-			let id = object["id"] as? String,
-			let name = object["name"] as? String
-		else {
-			return nil
-		}
-
-		return TimeZone(id: id, name: name)
-	}
-}
-
-private struct ChosenTimeZone: Codable, Hashable {
-	var id: String
-	var name: String
-}
-
-extension ChosenTimeZone: Defaults.Serializable {
-	static let bridge = ChosenTimeZoneBridge()
-}
-
-private struct ChosenTimeZoneBridge: Defaults.Bridge {
-	typealias Value = ChosenTimeZone
-	typealias Serializable = [String: Any]
-
-	func serialize(_ value: Value?) -> Serializable? {
-		guard let value else {
-			return nil
-		}
-
-		return ["id": value.id, "name": value.name]
-	}
-
-	func deserialize(_ object: Serializable?) -> Value? {
-		guard
-			let object,
-			let id = object["id"] as? String,
-			let name = object["name"] as? String
-		else {
-			return nil
-		}
-
-		return ChosenTimeZone(id: id, name: name)
-	}
-}
-
-private protocol BagForm {
-	associatedtype Element
-	var items: [Element] { get set }
-}
-
-extension BagForm {
-	var startIndex: Int {
-		items.startIndex
-	}
-
-	var endIndex: Int {
-		items.endIndex
-	}
-
-	mutating func insert(element: Element, at: Int) {
-		items.insert(element, at: at)
-	}
-
-	func index(after index: Int) -> Int {
-		items.index(after: index)
-	}
-
-	subscript(position: Int) -> Element {
-		get { items[position] }
-		set { items[position] = newValue }
-	}
-}
-
-private struct MyBag<Element: Defaults.NativeType>: BagForm, Defaults.CollectionSerializable, Defaults.NativeType {
-	var items: [Element]
-
-	init(_ elements: [Element]) {
-		self.items = elements
-	}
-}
-
-private struct CodableBag<Element: Defaults.Serializable & Codable>: BagForm, Defaults.CollectionSerializable, Codable {
-	var items: [Element]
-
-	init(_ elements: [Element]) {
-		self.items = elements
-	}
-}
-
-private protocol SetForm: SetAlgebra where Element: Hashable {
-	var store: Set<Element> { get set }
-}
-
-extension SetForm {
-	func contains(_ member: Element) -> Bool {
-		store.contains(member)
-	}
-
-	func union(_ other: Self) -> Self {
-		Self(store.union(other.store))
-	}
-
-	func intersection(_ other: Self) -> Self {
-		var setForm = Self()
-		setForm.store = store.intersection(other.store)
-		return setForm
-	}
-
-	func symmetricDifference(_ other: Self) -> Self {
-		var setForm = Self()
-		setForm.store = store.symmetricDifference(other.store)
-		return setForm
-	}
-
-	@discardableResult
-	mutating func insert(_ newMember: Element) -> (inserted: Bool, memberAfterInsert: Element) {
-		store.insert(newMember)
-	}
-
-	mutating func remove(_ member: Element) -> Element? {
-		store.remove(member)
-	}
-
-	mutating func update(with newMember: Element) -> Element? {
-		store.update(with: newMember)
-	}
-
-	mutating func formUnion(_ other: Self) {
-		store.formUnion(other.store)
-	}
-
-	mutating func formSymmetricDifference(_ other: Self) {
-		store.formSymmetricDifference(other.store)
-	}
-
-	mutating func formIntersection(_ other: Self) {
-		store.formIntersection(other.store)
-	}
-
-	func toArray() -> [Element] {
-		Array(store)
-	}
-}
-
-private struct MySet<Element: Defaults.NativeType & Hashable>: SetForm, Defaults.SetAlgebraSerializable, Defaults.NativeType {
-	var store: Set<Element>
-
-	init() {
-		self.store = []
-	}
-
-	init(_ elements: [Element]) {
-		self.store = Set(elements)
-	}
-}
-
-private struct CodableSet<Element: Defaults.Serializable & Codable & Hashable>: SetForm, Defaults.SetAlgebraSerializable, Codable {
-	var store: Set<Element>
-
-	init() {
-		self.store = []
-	}
-
-	init(_ elements: [Element]) {
-		self.store = Set(elements)
-	}
-}
-
-private enum EnumForm: String {
-	case tenMinutes = "10 Minutes"
-	case halfHour = "30 Minutes"
-	case oneHour = "1 Hour"
-}
-
-extension EnumForm: Defaults.NativeType {
-	typealias CodableForm = CodableEnumForm
-}
-
-private enum CodableEnumForm: String {
-	case tenMinutes = "10 Minutes"
-	case halfHour = "30 Minutes"
-	case oneHour = "1 Hour"
-}
-
-extension CodableEnumForm: Defaults.CodableType {
-	typealias NativeForm = EnumForm
-}
-
-private func setCodable(forKey keyName: String, data: some Codable) {
-	guard
-		let text = try? JSONEncoder().encode(data),
-		let string = String(data: text, encoding: .utf8)
-	else {
-		XCTAssert(false)
-		return
-	}
-
-	UserDefaults.standard.set(string, forKey: keyName)
-}
-
-extension Defaults.Keys {
-	fileprivate static let nativeArray = Key<[String]?>("arrayToNativeStaticArrayKey")
-}
-
-final class DefaultsMigrationTests: XCTestCase {
-	override func setUp() {
-		super.setUp()
-		Defaults.removeAll()
-	}
-
-	override func tearDown() {
-		super.tearDown()
-		Defaults.removeAll()
-	}
-
-	func testDataToNativeData() {
-		let answer = "Hello World!"
-		let keyName = "dataToNativeData"
-		let data = answer.data(using: .utf8)
-		setCodable(forKey: keyName, data: data)
-		let key = Defaults.Key<Data?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(answer, String(data: Defaults[key]!, encoding: .utf8))
-		let newName = " Hank Chen"
-		Defaults[key]?.append(newName.data(using: .utf8)!)
-		XCTAssertEqual(answer + newName, String(data: Defaults[key]!, encoding: .utf8))
-	}
-
-	func testArrayDataToNativeCollectionData() {
-		let answer = "Hello World!"
-		let keyName = "arrayDataToNativeCollectionData"
-		let data = answer.data(using: .utf8)
-		setCodable(forKey: keyName, data: [data])
-		let key = Defaults.Key<MyBag<Data>?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(answer, String(data: Defaults[key]!.first!, encoding: .utf8))
-		let newName = " Hank Chen"
-		Defaults[key]?[0].append(newName.data(using: .utf8)!)
-		XCTAssertEqual(answer + newName, String(data: Defaults[key]!.first!, encoding: .utf8))
-	}
-
-	func testArrayDataToCodableCollectionData() {
-		let answer = "Hello World!"
-		let keyName = "arrayDataToCodableCollectionData"
-		let data = answer.data(using: .utf8)
-		setCodable(forKey: keyName, data: CodableBag([data]))
-		let key = Defaults.Key<CodableBag<Data>?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(answer, String(data: Defaults[key]!.first!, encoding: .utf8))
-		let newName = " Hank Chen"
-		Defaults[key]?[0].append(newName.data(using: .utf8)!)
-		XCTAssertEqual(answer + newName, String(data: Defaults[key]!.first!, encoding: .utf8))
-	}
-
-	func testArrayDataToNativeSetAlgebraData() {
-		let answer = "Hello World!"
-		let keyName = "arrayDataToNativeSetAlgebraData"
-		let data = answer.data(using: .utf8)
-		setCodable(forKey: keyName, data: CodableSet([data]))
-		let key = Defaults.Key<CodableSet<Data>?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(answer, String(data: Defaults[key]!.store.first!, encoding: .utf8))
-		let newName = " Hank Chen"
-		Defaults[key]?.store.insert(newName.data(using: .utf8)!)
-		XCTAssertEqual(Set([answer.data(using: .utf8)!, newName.data(using: .utf8)!]), Defaults[key]?.store)
-	}
-
-	func testDateToNativeDate() {
-		let date = Date()
-		let keyName = "dateToNativeDate"
-		setCodable(forKey: keyName, data: date)
-		let key = Defaults.Key<Date?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(date, Defaults[key])
-		let newDate = Date()
-		Defaults[key] = newDate
-		XCTAssertEqual(newDate, Defaults[key])
-	}
-
-	func testDateToNativeCollectionDate() {
-		let date = Date()
-		let keyName = "dateToNativeCollectionDate"
-		setCodable(forKey: keyName, data: [date])
-		let key = Defaults.Key<MyBag<Date>?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(date, Defaults[key]!.first)
-		let newDate = Date()
-		Defaults[key]?[0] = newDate
-		XCTAssertEqual(newDate, Defaults[key]!.first)
-	}
-
-	func testDateToCodableCollectionDate() {
-		let date = Date()
-		let keyName = "dateToCodableCollectionDate"
-		setCodable(forKey: keyName, data: CodableBag([date]))
-		let key = Defaults.Key<CodableBag<Date>?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(date, Defaults[key]!.first)
-		let newDate = Date()
-		Defaults[key]?[0] = newDate
-		XCTAssertEqual(newDate, Defaults[key]!.first)
-	}
-
-	func testBoolToNativeBool() {
-		let bool = false
-		let keyName = "boolToNativeBool"
-		setCodable(forKey: keyName, data: bool)
-		let key = Defaults.Key<Bool?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key], bool)
-		let newBool = true
-		Defaults[key] = newBool
-		XCTAssertEqual(Defaults[key], newBool)
-	}
-
-	func testBoolToNativeCollectionBool() {
-		let bool = false
-		let keyName = "boolToNativeCollectionBool"
-		setCodable(forKey: keyName, data: [bool])
-		let key = Defaults.Key<MyBag<Bool>?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key]?[0], bool)
-		let newBool = true
-		Defaults[key]?[0] = newBool
-		XCTAssertEqual(Defaults[key]?[0], newBool)
-	}
-
-	func testBoolToCodableCollectionBool() {
-		let bool = false
-		let keyName = "boolToCodableCollectionBool"
-		setCodable(forKey: keyName, data: CodableBag([bool]))
-		let key = Defaults.Key<CodableBag<Bool>?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key]?[0], bool)
-		let newBool = true
-		Defaults[key]?[0] = newBool
-		XCTAssertEqual(Defaults[key]?[0], newBool)
-	}
-
-	func testIntToNativeInt() {
-		let int = Int.min
-		let keyName = "intToNativeInt"
-		setCodable(forKey: keyName, data: int)
-		let key = Defaults.Key<Int?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key], int)
-		let newInt = Int.max
-		Defaults[key] = newInt
-		XCTAssertEqual(Defaults[key], newInt)
-	}
-
-	func testIntToNativeCollectionInt() {
-		let int = Int.min
-		let keyName = "intToNativeCollectionInt"
-		setCodable(forKey: keyName, data: [int])
-		let key = Defaults.Key<MyBag<Int>?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key]?[0], int)
-		let newInt = Int.max
-		Defaults[key]?[0] = newInt
-		XCTAssertEqual(Defaults[key]?[0], newInt)
-	}
-
-	func testIntToCodableCollectionInt() {
-		let int = Int.min
-		let keyName = "intToCodableCollectionInt"
-		setCodable(forKey: keyName, data: CodableBag([int]))
-		let key = Defaults.Key<CodableBag<Int>?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key]?[0], int)
-		let newInt = Int.max
-		Defaults[key]?[0] = newInt
-		XCTAssertEqual(Defaults[key]?[0], newInt)
-	}
-
-	func testUIntToNativeUInt() {
-		let uInt = UInt.min
-		let keyName = "uIntToNativeUInt"
-		setCodable(forKey: keyName, data: uInt)
-		let key = Defaults.Key<UInt?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key], uInt)
-		let newUInt = UInt.max
-		Defaults[key] = newUInt
-		XCTAssertEqual(Defaults[key], newUInt)
-	}
-
-	func testUIntToNativeCollectionUInt() {
-		let uInt = UInt.min
-		let keyName = "uIntToNativeCollectionUInt"
-		setCodable(forKey: keyName, data: [uInt])
-		let key = Defaults.Key<MyBag<UInt>?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key]?[0], uInt)
-		let newUInt = UInt.max
-		Defaults[key]?[0] = newUInt
-		XCTAssertEqual(Defaults[key]?[0], newUInt)
-	}
-
-	func testUIntToCodableCollectionUInt() {
-		let uInt = UInt.min
-		let keyName = "uIntToCodableCollectionUInt"
-		setCodable(forKey: keyName, data: CodableBag([uInt]))
-		let key = Defaults.Key<CodableBag<UInt>?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key]?[0], uInt)
-		let newUInt = UInt.max
-		Defaults[key]?[0] = newUInt
-		XCTAssertEqual(Defaults[key]?[0], newUInt)
-	}
-
-	func testDoubleToNativeDouble() {
-		let double = Double.zero
-		let keyName = "doubleToNativeDouble"
-		setCodable(forKey: keyName, data: double)
-		let key = Defaults.Key<Double?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key], double)
-		let newDouble = Double.infinity
-		Defaults[key] = newDouble
-		XCTAssertEqual(Defaults[key], newDouble)
-	}
-
-	func testDoubleToNativeCollectionDouble() {
-		let double = Double.zero
-		let keyName = "doubleToNativeCollectionDouble"
-		setCodable(forKey: keyName, data: [double])
-		let key = Defaults.Key<MyBag<Double>?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key]?[0], double)
-		let newDouble = Double.infinity
-		Defaults[key]?[0] = newDouble
-		XCTAssertEqual(Defaults[key]?[0], newDouble)
-	}
-
-	func testDoubleToCodableCollectionDouble() {
-		let double = Double.zero
-		let keyName = "doubleToCodableCollectionDouble"
-		setCodable(forKey: keyName, data: CodableBag([double]))
-		let key = Defaults.Key<CodableBag<Double>?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key]?[0], double)
-		let newDouble = Double.infinity
-		Defaults[key]?[0] = newDouble
-		XCTAssertEqual(Defaults[key]?[0], newDouble)
-	}
-
-	func testFloatToNativeFloat() {
-		let float = Float.zero
-		let keyName = "floatToNativeFloat"
-		setCodable(forKey: keyName, data: float)
-		let key = Defaults.Key<Float?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key], float)
-		let newFloat = Float.infinity
-		Defaults[key] = newFloat
-		XCTAssertEqual(Defaults[key], newFloat)
-	}
-
-	func testFloatToNativeCollectionFloat() {
-		let float = Float.zero
-		let keyName = "floatToNativeCollectionFloat"
-		setCodable(forKey: keyName, data: [float])
-		let key = Defaults.Key<MyBag<Float>?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key]?[0], float)
-		let newFloat = Float.infinity
-		Defaults[key]?[0] = newFloat
-		XCTAssertEqual(Defaults[key]?[0], newFloat)
-	}
-
-	func testFloatToCodableCollectionFloat() {
-		let float = Float.zero
-		let keyName = "floatToCodableCollectionFloat"
-		setCodable(forKey: keyName, data: CodableBag([float]))
-		let key = Defaults.Key<CodableBag<Float>?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key]?[0], float)
-		let newFloat = Float.infinity
-		Defaults[key]?[0] = newFloat
-		XCTAssertEqual(Defaults[key]?[0], newFloat)
-	}
-
-	func testCGFloatToNativeCGFloat() {
-		let cgFloat = CGFloat.zero
-		let keyName = "cgFloatToNativeCGFloat"
-		setCodable(forKey: keyName, data: cgFloat)
-		let key = Defaults.Key<CGFloat?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key], cgFloat)
-		let newCGFloat = CGFloat.infinity
-		Defaults[key] = newCGFloat
-		XCTAssertEqual(Defaults[key], newCGFloat)
-	}
-
-	func testCGFloatToNativeCollectionCGFloat() {
-		let cgFloat = CGFloat.zero
-		let keyName = "cgFloatToNativeCollectionCGFloat"
-		setCodable(forKey: keyName, data: [cgFloat])
-		let key = Defaults.Key<MyBag<CGFloat>?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key]?[0], cgFloat)
-		let newCGFloat = CGFloat.infinity
-		Defaults[key]?[0] = newCGFloat
-		XCTAssertEqual(Defaults[key]?[0], newCGFloat)
-	}
-
-	func testCGFloatToCodableCollectionCGFloat() {
-		let cgFloat = CGFloat.zero
-		let keyName = "cgFloatToCodableCollectionCGFloat"
-		setCodable(forKey: keyName, data: CodableBag([cgFloat]))
-		let key = Defaults.Key<CodableBag<CGFloat>?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key]?[0], cgFloat)
-		let newCGFloat = CGFloat.infinity
-		Defaults[key]?[0] = newCGFloat
-		XCTAssertEqual(Defaults[key]?[0], newCGFloat)
-	}
-
-	func testInt8ToNativeInt8() {
-		let int8 = Int8.min
-		let keyName = "int8ToNativeInt8"
-		setCodable(forKey: keyName, data: int8)
-		let key = Defaults.Key<Int8?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key], int8)
-		let newInt8 = Int8.max
-		Defaults[key] = newInt8
-		XCTAssertEqual(Defaults[key], newInt8)
-	}
-
-	func testInt8ToNativeCollectionInt8() {
-		let int8 = Int8.min
-		let keyName = "int8ToNativeCollectionInt8"
-		setCodable(forKey: keyName, data: [int8])
-		let key = Defaults.Key<MyBag<Int8>?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key]?[0], int8)
-		let newInt8 = Int8.max
-		Defaults[key]?[0] = newInt8
-		XCTAssertEqual(Defaults[key]?[0], newInt8)
-	}
-
-	func testInt8ToCodableCollectionInt8() {
-		let int8 = Int8.min
-		let keyName = "int8ToCodableCollectionInt8"
-		setCodable(forKey: keyName, data: CodableBag([int8]))
-		let key = Defaults.Key<CodableBag<Int8>?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key]?[0], int8)
-		let newInt8 = Int8.max
-		Defaults[key]?[0] = newInt8
-		XCTAssertEqual(Defaults[key]?[0], newInt8)
-	}
-
-	func testUInt8ToNativeUInt8() {
-		let uInt8 = UInt8.min
-		let keyName = "uInt8ToNativeUInt8"
-		setCodable(forKey: keyName, data: uInt8)
-		let key = Defaults.Key<UInt8?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key], uInt8)
-		let newUInt8 = UInt8.max
-		Defaults[key] = newUInt8
-		XCTAssertEqual(Defaults[key], newUInt8)
-	}
-
-	func testUInt8ToNativeCollectionUInt8() {
-		let uInt8 = UInt8.min
-		let keyName = "uInt8ToNativeCollectionUInt8"
-		setCodable(forKey: keyName, data: [uInt8])
-		let key = Defaults.Key<MyBag<UInt8>?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key]?[0], uInt8)
-		let newUInt8 = UInt8.max
-		Defaults[key]?[0] = newUInt8
-		XCTAssertEqual(Defaults[key]?[0], newUInt8)
-	}
-
-	func testUInt8ToCodableCollectionUInt8() {
-		let uInt8 = UInt8.min
-		let keyName = "uInt8ToCodableCollectionUInt8"
-		setCodable(forKey: keyName, data: CodableBag([uInt8]))
-		let key = Defaults.Key<CodableBag<UInt8>?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key]?[0], uInt8)
-		let newUInt8 = UInt8.max
-		Defaults[key]?[0] = newUInt8
-		XCTAssertEqual(Defaults[key]?[0], newUInt8)
-	}
-
-	func testInt16ToNativeInt16() {
-		let int16 = Int16.min
-		let keyName = "int16ToNativeInt16"
-		setCodable(forKey: keyName, data: int16)
-		let key = Defaults.Key<Int16?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key], int16)
-		let newInt16 = Int16.max
-		Defaults[key] = newInt16
-		XCTAssertEqual(Defaults[key], newInt16)
-	}
-
-	func testInt16ToNativeCollectionInt16() {
-		let int16 = Int16.min
-		let keyName = "int16ToNativeCollectionInt16"
-		setCodable(forKey: keyName, data: [int16])
-		let key = Defaults.Key<MyBag<Int16>?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key]?[0], int16)
-		let newInt16 = Int16.max
-		Defaults[key]?[0] = newInt16
-		XCTAssertEqual(Defaults[key]?[0], newInt16)
-	}
-
-	func testInt16ToCodableCollectionInt16() {
-		let int16 = Int16.min
-		let keyName = "int16ToCodableCollectionInt16"
-		setCodable(forKey: keyName, data: CodableBag([int16]))
-		let key = Defaults.Key<CodableBag<Int16>?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key]?[0], int16)
-		let newInt16 = Int16.max
-		Defaults[key]?[0] = newInt16
-		XCTAssertEqual(Defaults[key]?[0], newInt16)
-	}
-
-	func testUInt16ToNativeUInt16() {
-		let uInt16 = UInt16.min
-		let keyName = "uInt16ToNativeUInt16"
-		setCodable(forKey: keyName, data: uInt16)
-		let key = Defaults.Key<UInt16?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key], uInt16)
-		let newUInt16 = UInt16.max
-		Defaults[key] = newUInt16
-		XCTAssertEqual(Defaults[key], newUInt16)
-	}
-
-	func testUInt16ToNativeCollectionUInt16() {
-		let uInt16 = UInt16.min
-		let keyName = "uInt16ToNativeCollectionUInt16"
-		setCodable(forKey: keyName, data: [uInt16])
-		let key = Defaults.Key<MyBag<UInt16>?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key]?[0], uInt16)
-		let newUInt16 = UInt16.max
-		Defaults[key]?[0] = newUInt16
-		XCTAssertEqual(Defaults[key]?[0], newUInt16)
-	}
-
-	func testUInt16ToCodableCollectionUInt16() {
-		let uInt16 = UInt16.min
-		let keyName = "uInt16ToCodableCollectionUInt16"
-		setCodable(forKey: keyName, data: CodableBag([uInt16]))
-		let key = Defaults.Key<CodableBag<UInt16>?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key]?[0], uInt16)
-		let newUInt16 = UInt16.max
-		Defaults[key]?[0] = newUInt16
-		XCTAssertEqual(Defaults[key]?[0], newUInt16)
-	}
-
-	func testInt32ToNativeInt32() {
-		let int32 = Int32.min
-		let keyName = "int32ToNativeInt32"
-		setCodable(forKey: keyName, data: int32)
-		let key = Defaults.Key<Int32?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key], int32)
-		let newInt32 = Int32.max
-		Defaults[key] = newInt32
-		XCTAssertEqual(Defaults[key], newInt32)
-	}
-
-	func testInt32ToNativeCollectionInt32() {
-		let int32 = Int32.min
-		let keyName = "int32ToNativeCollectionInt32"
-		setCodable(forKey: keyName, data: [int32])
-		let key = Defaults.Key<MyBag<Int32>?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key]?[0], int32)
-		let newInt32 = Int32.max
-		Defaults[key]?[0] = newInt32
-		XCTAssertEqual(Defaults[key]?[0], newInt32)
-	}
-
-	func testInt32ToCodableCollectionInt32() {
-		let int32 = Int32.min
-		let keyName = "int32ToCodableCollectionInt32"
-		setCodable(forKey: keyName, data: CodableBag([int32]))
-		let key = Defaults.Key<CodableBag<Int32>?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key]?[0], int32)
-		let newInt32 = Int32.max
-		Defaults[key]?[0] = newInt32
-		XCTAssertEqual(Defaults[key]?[0], newInt32)
-	}
-
-	func testUInt32ToNativeUInt32() {
-		let uInt32 = UInt32.min
-		let keyName = "uInt32ToNativeUInt32"
-		setCodable(forKey: keyName, data: uInt32)
-		let key = Defaults.Key<UInt32?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key], uInt32)
-		let newUInt32 = UInt32.max
-		Defaults[key] = newUInt32
-		XCTAssertEqual(Defaults[key], newUInt32)
-	}
-
-	func testUInt32ToNativeCollectionUInt32() {
-		let uInt32 = UInt32.min
-		let keyName = "uInt32ToNativeCollectionUInt32"
-		setCodable(forKey: keyName, data: [uInt32])
-		let key = Defaults.Key<MyBag<UInt32>?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key]?[0], uInt32)
-		let newUInt32 = UInt32.max
-		Defaults[key]?[0] = newUInt32
-		XCTAssertEqual(Defaults[key]?[0], newUInt32)
-	}
-
-	func testUInt32ToCodableCollectionUInt32() {
-		let uInt32 = UInt32.min
-		let keyName = "uInt32ToCodableCollectionUInt32"
-		setCodable(forKey: keyName, data: CodableBag([uInt32]))
-		let key = Defaults.Key<CodableBag<UInt32>?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key]?[0], uInt32)
-		let newUInt32 = UInt32.max
-		Defaults[key]?[0] = newUInt32
-		XCTAssertEqual(Defaults[key]?[0], newUInt32)
-	}
-
-	func testInt64ToNativeInt64() {
-		let int64 = Int64.min
-		let keyName = "int64ToNativeInt64"
-		setCodable(forKey: keyName, data: int64)
-		let key = Defaults.Key<Int64?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key], int64)
-		let newInt64 = Int64.max
-		Defaults[key] = newInt64
-		XCTAssertEqual(Defaults[key], newInt64)
-	}
-
-	func testInt64ToNativeCollectionInt64() {
-		let int64 = Int64.min
-		let keyName = "int64ToNativeCollectionInt64"
-		setCodable(forKey: keyName, data: [int64])
-		let key = Defaults.Key<MyBag<Int64>?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key]?[0], int64)
-		let newInt64 = Int64.max
-		Defaults[key]?[0] = newInt64
-		XCTAssertEqual(Defaults[key]?[0], newInt64)
-	}
-
-	func testInt64ToCodableCollectionInt64() {
-		let int64 = Int64.min
-		let keyName = "int64ToCodableCollectionInt64"
-		setCodable(forKey: keyName, data: CodableBag([int64]))
-		let key = Defaults.Key<CodableBag<Int64>?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key]?[0], int64)
-		let newInt64 = Int64.max
-		Defaults[key]?[0] = newInt64
-		XCTAssertEqual(Defaults[key]?[0], newInt64)
-	}
-
-	func testUInt64ToNativeUInt64() {
-		let uInt64 = UInt64.min
-		let keyName = "uInt64ToNativeUInt64"
-		setCodable(forKey: keyName, data: uInt64)
-		let key = Defaults.Key<UInt64?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key], uInt64)
-		let newUInt64 = UInt64.max
-		Defaults[key] = newUInt64
-		XCTAssertEqual(Defaults[key], newUInt64)
-	}
-
-	func testUInt64ToNativeCollectionUInt64() {
-		let uInt64 = UInt64.min
-		let keyName = "uInt64ToNativeCollectionUInt64"
-		setCodable(forKey: keyName, data: [uInt64])
-		let key = Defaults.Key<MyBag<UInt64>?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key]?[0], uInt64)
-		let newUInt64 = UInt64.max
-		Defaults[key]?[0] = newUInt64
-		XCTAssertEqual(Defaults[key]?[0], newUInt64)
-	}
-
-	func testUInt64ToCodableCollectionUInt64() {
-		let uInt64 = UInt64.min
-		let keyName = "uInt64ToCodableCollectionUInt64"
-		setCodable(forKey: keyName, data: CodableBag([uInt64]))
-		let key = Defaults.Key<CodableBag<UInt64>?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key]?[0], uInt64)
-		let newUInt64 = UInt64.max
-		Defaults[key]?[0] = newUInt64
-		XCTAssertEqual(Defaults[key]?[0], newUInt64)
-	}
-
-	func testArrayURLToNativeArrayURL() {
-		let url = URL(string: "https://sindresorhus.com")!
-		let keyName = "arrayURLToNativeArrayURL"
-		setCodable(forKey: keyName, data: [url])
-		let key = Defaults.Key<[URL]?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key]?[0], url)
-		let newURL = URL(string: "https://example.com")!
-		Defaults[key]?.append(newURL)
-		XCTAssertEqual(Defaults[key]?[1], newURL)
-	}
-
-	func testArrayURLToNativeCollectionURL() {
-		let url = URL(string: "https://sindresorhus.com")!
-		let keyName = "arrayURLToNativeCollectionURL"
-		setCodable(forKey: keyName, data: [url])
-		let key = Defaults.Key<MyBag<URL>?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key]?[0], url)
-		let newURL = URL(string: "https://example.com")!
-		Defaults[key]?.insert(element: newURL, at: 1)
-		XCTAssertEqual(Defaults[key]?[1], newURL)
-	}
-
-	func testArrayToNativeArray() {
-		let keyName = "arrayToNativeArrayKey"
-		setCodable(forKey: keyName, data: ["a", "b", "c"])
-		let key = Defaults.Key<[String]>(keyName, default: [])
-		Defaults.migrate(key, to: .v5)
-		let newValue = "d"
-		Defaults[key].append(newValue)
-		XCTAssertEqual(Defaults[key][0], "a")
-		XCTAssertEqual(Defaults[key][1], "b")
-		XCTAssertEqual(Defaults[key][2], "c")
-		XCTAssertEqual(Defaults[key][3], newValue)
-	}
-
-	func testArrayToNativeStaticOptionalArray() {
-		let keyName = "arrayToNativeStaticArrayKey"
-		setCodable(forKey: keyName, data: ["a", "b", "c"])
-		Defaults.migrate(.nativeArray, to: .v5)
-		let newValue = "d"
-		Defaults[.nativeArray]?.append(newValue)
-		XCTAssertEqual(Defaults[.nativeArray]?[0], "a")
-		XCTAssertEqual(Defaults[.nativeArray]?[1], "b")
-		XCTAssertEqual(Defaults[.nativeArray]?[2], "c")
-		XCTAssertEqual(Defaults[.nativeArray]?[3], newValue)
-	}
-
-	func testArrayToNativeOptionalArray() {
-		let keyName = "arrayToNativeArrayKey"
-		setCodable(forKey: keyName, data: ["a", "b", "c"])
-		let key = Defaults.Key<[String]?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		let newValue = "d"
-		Defaults[key]?.append(newValue)
-		XCTAssertEqual(Defaults[key]?[0], "a")
-		XCTAssertEqual(Defaults[key]?[1], "b")
-		XCTAssertEqual(Defaults[key]?[2], "c")
-		XCTAssertEqual(Defaults[key]?[3], newValue)
-	}
-
-	func testArrayDictionaryStringIntToNativeArray() {
-		let keyName = "arrayDictionaryStringIntToNativeArray"
-		setCodable(forKey: keyName, data: [["a": 0, "b": 1]])
-		let key = Defaults.Key<[[String: Int]]?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		let newValue = 2
-		let newDictionary = ["d": 3]
-		Defaults[key]?[0]["c"] = newValue
-		Defaults[key]?.append(newDictionary)
-		XCTAssertEqual(Defaults[key]?[0]["a"], 0)
-		XCTAssertEqual(Defaults[key]?[0]["b"], 1)
-		XCTAssertEqual(Defaults[key]?[0]["c"], newValue)
-		XCTAssertEqual(Defaults[key]?[1]["d"], newDictionary["d"])
-	}
-
-	func testArrayToNativeSet() {
-		let keyName = "arrayToNativeSet"
-		setCodable(forKey: keyName, data: ["a", "b", "c"])
-		let key = Defaults.Key<Set<String>?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		let newValue = "d"
-		Defaults[key]?.insert(newValue)
-		XCTAssertEqual(Defaults[key], Set(["a", "b", "c", "d"]))
-	}
-
-	func testArrayToNativeCollectionType() {
-		let string = "Hello World!"
-		let keyName = "arrayToNativeCollectionType"
-		setCodable(forKey: keyName, data: [string])
-		let key = Defaults.Key<MyBag<String>?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key]?[0], string)
-		let newString = "Hank Chen"
-		Defaults[key]?[0] = newString
-		XCTAssertEqual(Defaults[key]?[0], newString)
-	}
-
-	func testArrayToCodableCollectionType() {
-		let keyName = "arrayToCodableCollectionType"
-		setCodable(forKey: keyName, data: CodableBag(["a", "b", "c"]))
-		let key = Defaults.Key<CodableBag<String>?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		let newValue = "d"
-		Defaults[key]?.insert(element: newValue, at: 3)
-		XCTAssertEqual(Defaults[key]?[0], "a")
-		XCTAssertEqual(Defaults[key]?[1], "b")
-		XCTAssertEqual(Defaults[key]?[2], "c")
-		XCTAssertEqual(Defaults[key]?[3], newValue)
-	}
-
-	func testArrayAndCodableElementToNativeCollectionType() {
-		let keyName = "arrayAndCodableElementToNativeCollectionType"
-		setCodable(forKey: keyName, data: [CodableTimeZone(id: "0", name: "Asia/Taipei")])
-		let key = Defaults.Key<MyBag<TimeZone>?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key]?[0].id, "0")
-		let newName = "Asia/Tokyo"
-		Defaults[key]?.insert(element: .init(id: "1", name: newName), at: 1)
-		XCTAssertEqual(Defaults[key]?[1].name, newName)
-	}
-
-	func testArrayAndCodableElementToNativeSetAlgebraType() {
-		let keyName = "arrayAndCodableElementToNativeSetAlgebraType"
-		setCodable(forKey: keyName, data: [CodableTimeZone(id: "0", name: "Asia/Taipei")])
-		let key = Defaults.Key<MySet<TimeZone>?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key]?.store.first?.id, "0")
-		let newName = "Asia/Tokyo"
-		Defaults[key]?.insert(.init(id: "1", name: newName))
-		XCTAssertEqual(Set([TimeZone(id: "0", name: "Asia/Taipei"), TimeZone(id: "1", name: newName)]), Defaults[key]?.store)
-	}
-
-	func testCodableToNativeType() {
-		let keyName = "codableCodableToNativeType"
-		setCodable(forKey: keyName, data: CodableTimeZone(id: "0", name: "Asia/Taipei"))
-		let key = Defaults.Key<TimeZone>(keyName, default: .init(id: "1", name: "Asia/Tokio"))
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key].id, "0")
-		let newName = "Asia/Tokyo"
-		Defaults[key].name = newName
-		XCTAssertEqual(Defaults[key].name, newName)
-	}
-
-	func testCodableToNativeOptionalType() {
-		let keyName = "codableCodableToNativeOptionalType"
-		setCodable(forKey: keyName, data: CodableTimeZone(id: "0", name: "Asia/Taipei"))
-		let key = Defaults.Key<TimeZone?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key]?.id, "0")
-		let newName = "Asia/Tokyo"
-		Defaults[key]?.name = newName
-		XCTAssertEqual(Defaults[key]?.name, newName)
-	}
-
-	func testArrayAndCodableElementToNativeArray() {
-		let keyName = "codableArrayAndCodableElementToNativeArray"
-		setCodable(forKey: keyName, data: [CodableTimeZone(id: "0", name: "Asia/Taipei")])
-		let key = Defaults.Key<[TimeZone]?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key]?[0].id, "0")
-		let newName = "Asia/Tokyo"
-		Defaults[key]?[0].name = newName
-		XCTAssertEqual(Defaults[key]?[0].name, newName)
-	}
-
-	func testArrayAndCodableElementToNativeSet() {
-		let keyName = "arrayAndCodableElementToNativeSet"
-		setCodable(forKey: keyName, data: [CodableTimeZone(id: "0", name: "Asia/Taipei")])
-		let key = Defaults.Key<Set<TimeZone>?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key], Set([TimeZone(id: "0", name: "Asia/Taipei")]))
-		let newId = "1"
-		let newName = "Asia/Tokyo"
-		Defaults[key]?.insert(.init(id: newId, name: newName))
-		XCTAssertEqual(Defaults[key], Set([TimeZone(id: "0", name: "Asia/Taipei"), TimeZone(id: newId, name: newName)]))
-	}
-
-	func testCodableToNativeCodableOptionalType() {
-		let keyName = "codableToNativeCodableOptionalType"
-		setCodable(forKey: keyName, data: ChosenTimeZone(id: "0", name: "Asia/Taipei"))
-		let key = Defaults.Key<ChosenTimeZone?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key]?.id, "0")
-		let newName = "Asia/Tokyo"
-		Defaults[key]?.name = newName
-		XCTAssertEqual(Defaults[key]?.name, newName)
-	}
-
-	func testCodableArrayToNativeCodableArrayType() {
-		let keyName = "codableToNativeCodableArrayType"
-		setCodable(forKey: keyName, data: [ChosenTimeZone(id: "0", name: "Asia/Taipei")])
-		let key = Defaults.Key<[ChosenTimeZone]?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key]?[0].id, "0")
-		let newName = "Asia/Tokyo"
-		Defaults[key]?[0].name = newName
-		XCTAssertEqual(Defaults[key]?[0].name, newName)
-	}
-
-	func testCodableArrayToNativeCollectionType() {
-		let keyName = "codableToNativeCollectionType"
-		setCodable(forKey: keyName, data: CodableBag([ChosenTimeZone(id: "0", name: "Asia/Taipei")]))
-		let key = Defaults.Key<CodableBag<ChosenTimeZone>?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key]?[0].id, "0")
-		let newName = "Asia/Tokyo"
-		Defaults[key]?[0].name = newName
-		XCTAssertEqual(Defaults[key]?[0].name, newName)
-	}
-
-	func testDictionaryToNativelyDictionary() {
-		let keyName = "codableDictionaryToNativelyDictionary"
-		setCodable(forKey: keyName, data: ["Hank": "Chen"])
-		let key = Defaults.Key<[String: String]?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key]?["Hank"], "Chen")
-	}
-
-	func testDictionaryAndCodableValueToNativeDictionary() {
-		let keyName = "codableArrayAndCodableElementToNativeArray"
-		setCodable(forKey: keyName, data: ["0": CodableTimeZone(id: "0", name: "Asia/Taipei")])
-		let key = Defaults.Key<[String: TimeZone]?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key]?["0"]?.id, "0")
-		let newName = "Asia/Tokyo"
-		Defaults[key]?["0"]?.name = newName
-		XCTAssertEqual(Defaults[key]?["0"]?.name, newName)
-	}
-
-	func testDictionaryCodableKeyAndCodableValueToNativeDictionary() {
-		let keyName = "dictionaryCodableKeyAndCodableValueToNativeDictionary"
-		setCodable(forKey: keyName, data: [123: CodableTimeZone(id: "0", name: "Asia/Taipei")])
-		let key = Defaults.Key<[UInt32: TimeZone]?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key]?[123]?.id, "0")
-		let newName = "Asia/Tokyo"
-		Defaults[key]?[123]?.name = newName
-		XCTAssertEqual(Defaults[key]?[123]?.name, newName)
-	}
-
-	func testDictionaryCustomKeyAndCodableValueToNativeDictionary() {
-		let keyName = "dictionaryCustomAndCodableValueToNativeDictionary"
-		setCodable(forKey: keyName, data: [1234: CodableTimeZone(id: "0", name: "Asia/Taipei")])
-		let key = Defaults.Key<[UniqueID: TimeZone]?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		let id = UniqueID(id: 1234)
-		XCTAssertEqual(Defaults[key]?[id]?.id, "0")
-		let newName = "Asia/Tokyo"
-		Defaults[key]?[id]?.name = newName
-		XCTAssertEqual(Defaults[key]?[id]?.name, newName)
-	}
-
-	func testNestedDictionaryCustomKeyAndCodableValueToNativeNestedDictionary() {
-		let keyName = "nestedDictionaryCustomKeyAndCodableValueToNativeNestedDictionary"
-		setCodable(forKey: keyName, data: [12_345: [1234: CodableTimeZone(id: "0", name: "Asia/Taipei")]])
-		let key = Defaults.Key<[UniqueID: [UniqueID: TimeZone]]?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		let firstId = UniqueID(id: 12_345)
-		let secondId = UniqueID(id: 1234)
-		XCTAssertEqual(Defaults[key]?[firstId]?[secondId]?.id, "0")
-		let newName = "Asia/Tokyo"
-		Defaults[key]?[firstId]?[secondId]?.name = newName
-		XCTAssertEqual(Defaults[key]?[firstId]?[secondId]?.name, newName)
-	}
-
-	func testEnumToNativeEnum() {
-		let keyName = "enumToNativeEnum"
-		setCodable(forKey: keyName, data: CodableEnumForm.tenMinutes)
-		let key = Defaults.Key<EnumForm?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key], .tenMinutes)
-		Defaults[key] = .halfHour
-		XCTAssertEqual(Defaults[key], .halfHour)
-	}
-
-	func testArrayEnumToNativeArrayEnum() {
-		let keyName = "arrayEnumToNativeArrayEnum"
-		setCodable(forKey: keyName, data: [CodableEnumForm.tenMinutes])
-		let key = Defaults.Key<[EnumForm]?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key]?[0], .tenMinutes)
-		Defaults[key]?.append(.halfHour)
-		XCTAssertEqual(Defaults[key]?[1], .halfHour)
-	}
-
-	func testArrayEnumToNativeSetEnum() {
-		let keyName = "arrayEnumToNativeSetEnum"
-		setCodable(forKey: keyName, data: Set([CodableEnumForm.tenMinutes]))
-		let key = Defaults.Key<Set<EnumForm>?>(keyName)
-		Defaults.migrate(key, to: .v5)
-		XCTAssertEqual(Defaults[key]?.first, .tenMinutes)
-		Defaults[key]?.insert(.halfHour)
-		XCTAssertEqual(Defaults[key], Set([.tenMinutes, .halfHour]))
-	}
-}
diff --git a/migration.md b/migration.md
deleted file mode 100644
index d6e6945..0000000
--- a/migration.md
+++ /dev/null
@@ -1,405 +0,0 @@
-# Migration guide from v4 to v5
-
-**Warning: Test the migration thoroughly in your app. It might cause unintended data loss if you're not careful.**
-
-## Summary
-
-We have improved the stored representation of types. Some types will require migration. Previously, all `Codable` types were serialized to a JSON string and stored as a `UserDefaults` string. `Defaults` is now able to store more types using the appropriate native `UserDefaults` type.
-
-- The following types require no changes:
-	- `Int(8/16/32/64)`
-	- `UInt(8/16/32/64)`
-	- `Double`
-	- `CGFloat`
-	- `Float`
-	- `String`
-	- `Bool`
-	- `Date`
-	- `Data`
-	- `URL`
-- Custom types (`struct`, `enum`, etc.) must now conform to `Defaults.Serializable` (in addition to `Codable`).
-- `Array`, `Set`, and `Dictionary` will need to be manually migrated with `Defaults.migrate()`.
-
----
-
-In v4, `Defaults` stored many types as a JSON string.\
-In v5, `Defaults` stores many types as native `UserDefaults` types.
-
-```swift
-// v4
-let key = Defaults.Key<[Int]>("key", default: [0, 1])
-
-UserDefaults.standard.string(forKey: "key")
-//=> "[0, 1]"
-```
-
-```swift
-// v5
-let key = Defaults.Key<[Int]>("key", default: [0, 1])
-
-UserDefaults.standard.dictionary(forKey: "key")
-//=> [0, 1]
-```
-
-## Issues
-
-1. **The compiler complains that `Defaults.Key<Value>` does not conform to `Defaults.Serializable`.**
-	Since we replaced `Codable` with `Defaults.Serializable`, `Key<Value>` will have to conform to `Value: Defaults.Serializable`.
-	For this situation, please follow the guides below:
-	- [From `Codable` struct in Defaults v4 to `Codable` struct in Defaults v5](#from-codable-struct-in-defaults-v4-to-codable-struct-in-defaults-v5)
-	- [From `Codable` enum in Defaults v4 to `Codable` enum in Defaults v5](#from-codable-enum-in-defaults-v4-to-codable-enum-in-defaults-v5)
-
-2. **The previous value in `UserDefaults` is not readable. (for example, `Defaults[.array]` returns `nil`).**
-	In v5, `Defaults` reads value from `UserDefaults` as a natively supported type, but since `UserDefaults` only contains JSON string before migration for `Codable` types, `Defaults` will not be able to work with it. For this situation, `Defaults` provides the `Defaults.migrate()` method to automate the migration process.
-	- [From `Codable` `Array/Dictionary/Set` in Defaults v4 to native `Array/Dictionary/Set`(with natively supported elements) in Defaults v5](#from-codable-arraydictionaryset-in-defaults-v4-to-native-arraydictionaryset-with-natively-supported-elements-in-defaults-v5)
-	- [From `Codable` `Array/Dictionary/Set` in Defaults v4 to native `Array/Dictionary/Set` (with codable elements) in Defaults v5](#from-codable-arraydictionaryset-in-defaults-v4-to-native-arraydictionaryset-with-codable-elements-in-defaults-v5)
-
-## Testing
-
-We recommend doing some manual testing after migrating.
-
-For example, let's say you are trying to migrate an array of `Codable` string to a native array.
-
-1. Get the previous value in `UserDefaults` (using `defaults` command or whatever you want).
-
-```swift
-let string = "[\"a\",\"b\",\"c\"]"
-```
-
-2. Insert the above value into `UserDefaults`.
-
-```swift
-UserDefaults.standard.set(string, forKey: "testKey")
-```
-
-3. Call `Defaults.migrate()` and then use `Defaults` to get its value.
-
-```swift
-let key = Defaults.Key<[String]>("testKey", default: [])
-Defaults.migrate(key, to: .v5)
-
-Defaults[key] //=> [a, b, c]
-```
-
-## Migrations
-
-### From `Codable` struct in Defaults v4 to `Codable` struct in Defaults v5
-
-In v4, `struct` had to conform to `Codable` to store it as a JSON string.
-
-In v5, `struct` has to conform to `Codable` and `Defaults.Serializable` to store it as a JSON string.
-
-#### Before migration
-
-```swift
-private struct TimeZone: Codable {
-	var id: String
-	var name: String
-}
-
-extension Defaults.Keys {
-	static let timezone = Defaults.Key<TimeZone?>("TimeZone")
-}
-```
-
-#### Migration steps
-
-1. Make `TimeZone` conform to `Defaults.Serializable`.
-
-```swift
-private struct TimeZone: Codable, Defaults.Serializable {
-	var id: String
-	var name: String
-}
-```
-
-2. Now `Defaults[.timezone]` should be readable.
-
-### From `Codable` enum in Defaults v4 to `Codable` enum in Defaults v5
-
-In v4, `enum` had to conform to `Codable` to store it as a JSON string.
-
-In v5, `enum` has to conform to `Codable` and `Defaults.Serializable` to store it as a JSON string.
-
-#### Before migration
-
-```swift
-private enum Period: String, Codable {
-	case tenMinutes = "10 Minutes"
-	case halfHour = "30 Minutes"
-	case oneHour = "1 Hour"
-}
-
-extension Defaults.Keys {
-	static let period = Defaults.Key<Period?>("period")
-}
-```
-
-#### Migration steps
-
-1. Make `Period` conform to `Defaults.Serializable`.
-
-```swift
-private enum Period: String, Defaults.Serializable, Codable {
-	case tenMinutes = "10 Minutes"
-	case halfHour = "30 Minutes"
-	case oneHour = "1 Hour"
-}
-```
-
-2. Now `Defaults[.period]` should be readable.
-
-### From `Codable` `Array/Dictionary/Set` in Defaults v4 to native `Array/Dictionary/Set` (with natively supported elements) in Defaults v5
-
-In v4, `Defaults` stored array/dictionary as a JSON string: `"[\"a\", \"b\", \"c\"]"`.
-
-In v5, `Defaults` stores it as a native array/dictionary with natively supported elements: `["a", "b", "c"]`.
-
-#### Before migration
-
-```swift
-extension Defaults.Keys {
-	static let arrayString = Defaults.Key<[String]?>("arrayString")
-	static let setString = Defaults.Key<Set<String>?>("setString")
-	static let dictionaryStringInt = Defaults.Key<[String: Int]?>("dictionaryStringInt")
-	static let dictionaryStringIntInArray = Defaults.Key<[[String: Int]]?>("dictionaryStringIntInArray")
-}
-```
-
-#### Migration steps
-
-1. **Call `Defaults.migrate(.arrayString, to: .v5)`, `Defaults.migrate(.setString, to: .v5)`, `Defaults.migrate(.dictionaryStringInt, to: .v5)`, `Defaults.migrate(.dictionaryStringIntInArray, to: .v5)`.**
-2. Now `Defaults[.arrayString]`, `Defaults.[.setString]`, `Defaults[.dictionaryStringInt]`, `Defaults[.dictionaryStringIntInArray]` should be readable.
-
-### From `Codable` `Array/Dictionary/Set` in Defaults v4 to native `Array/Dictionary/Set` (with `Codable` elements) in Defaults v5
-
-In v4, `Defaults` would store array/dictionary as a single JSON string: `"{\"id\": \"0\", \"name\": \"Asia/Taipei\"}"`, `"[\"10 Minutes\", \"30 Minutes\"]"`.
-
-In v5, `Defaults` will store it as a native array/dictionary with `Codable` elements: `{id: 0, name: "Asia/Taipei"}`, `["10 Minutes", "30 Minutes"]`.
-
-#### Before migration
-
-```swift
-private struct TimeZone: Hashable, Codable {
-	var id: String
-	var name: String
-}
-
-private enum Period: String, Hashable, Codable {
-	case tenMinutes = "10 Minutes"
-	case halfHour = "30 Minutes"
-	case oneHour = "1 Hour"
-}
-
-extension Defaults.Keys {
-	static let arrayTimezone = Defaults.Key<[TimeZone]?>("arrayTimezone")
-	static let setTimezone = Defaults.Key<[TimeZone]?>("setTimezone")
-	static let arrayPeriod = Defaults.Key<[Period]?>("arrayPeriod")
-	static let setPeriod = Defaults.Key<[Period]?>("setPeriod")
-	static let dictionaryTimezone = Defaults.Key<[String: TimeZone]?>("dictionaryTimezone")
-	static let dictionaryPeriod = Defaults.Key<[String: Period]?>("dictionaryPeriod")
-}
-```
-
-#### Migration steps
-
-1. Make `TimeZone` and `Period` conform to `Defaults.Serializable`.
-
-```swift
-private struct TimeZone: Hashable, Codable, Defaults.Serializable {
-	var id: String
-	var name: String
-}
-
-private enum Period: String, Hashable, Codable, Defaults.Serializable {
-	case tenMinutes = "10 Minutes"
-	case halfHour = "30 Minutes"
-	case oneHour = "1 Hour"
-}
-```
-
-2. **Call `Defaults.migrate(.arrayTimezone, to: .v5)`, `Defaults.migrate(.setTimezone, to: .v5)`, `Defaults.migrate(.dictionaryTimezone, to: .v5)`, `Defaults.migrate(.arrayPeriod, to: .v5)`, `Defaults.migrate(.setPeriod, to: .v5)` , `Defaults.migrate(.dictionaryPeriod, to: .v5)`.**
-3. Now `Defaults[.arrayTimezone]`, `Defaults[.setTimezone]`, `Defaults[.dictionaryTimezone]`, `Defaults[.arrayPeriod]`, `Defaults[.setPeriod]` , `Defaults[.dictionaryPeriod]` should be readable.
-
----
-
-## Optional migrations
-
-### From `Codable` enum in Defaults v4 to `RawRepresentable` enum in Defaults v5 *(Optional)*
-
-In v4, `Defaults` will store `enum` as a JSON string: `"10 Minutes"`.
-
-In v5, `Defaults` can store `enum` as a native string: `10 Minutes`.
-
-#### Before migration
-
-```swift
-private enum Period: String, Codable {
-	case tenMinutes = "10 Minutes"
-	case halfHour = "30 Minutes"
-	case oneHour = "1 Hour"
-}
-
-extension Defaults.Keys {
-	static let period = Defaults.Key<Period?>("period")
-}
-```
-
-#### Migration steps
-
-1. Create another enum called `CodablePeriod` and create an extension of it. Make the extension conform to `Defaults.CodableType` and its associated type `NativeForm` to `Period`.
-
-```swift
-private enum CodablePeriod: String {
-	case tenMinutes = "10 Minutes"
-	case halfHour = "30 Minutes"
-	case oneHour = "1 Hour"
-}
-
-extension CodablePeriod: Defaults.CodableType {
-	typealias NativeForm = Period
-}
-```
-
-2. Remove `Codable` conformance so `Period` can be stored natively.
-
-```swift
-private enum Period: String {
-	case tenMinutes = "10 Minutes"
-	case halfHour = "30 Minutes"
-	case oneHour = "1 Hour"
-}
-```
-
-3. Create an extension of `Period` that conforms to `Defaults.NativeType`. Its `CodableForm` should be `CodablePeriod`.
-
-```swift
-extension Period: Defaults.NativeType {
-	typealias CodableForm = CodablePeriod
-}
-```
-
-4. **Call `Defaults.migrate(.period)`**
-5. Now `Defaults[.period]` should be readable.
-
-You can also instead implement the `toNative` function in `Defaults.CodableType` for flexibility:
-
-```swift
-extension CodablePeriod: Defaults.CodableType {
-	typealias NativeForm = Period
-
-	public func toNative() -> Period {
-		switch self {
-		case .tenMinutes:
-			return .tenMinutes
-		case .halfHour:
-			return .halfHour
-		case .oneHour:
-			return .oneHour
-		}
-	}
-}
-```
-
-### From `Codable` struct in Defaults v4 to `Dictionary` in Defaults v5 *(Optional)*
-
-This happens when you have a struct which is stored as a `Codable` JSON string before, but now you want it to be stored as a native `UserDefaults` dictionary.
-
-#### Before migration
-
-```swift
-private struct TimeZone: Codable {
-	var id: String
-	var name: String
-}
-
-extension Defaults.Keys {
-	static let timezone = Defaults.Key<TimeZone?>("TimeZone")
-	static let arrayTimezone = Defaults.Key<[TimeZone]?>("arrayTimezone")
-	static let setTimezone = Defaults.Key<Set<TimeZone>?>("setTimezone")
-	static let dictionaryTimezone = Defaults.Key<[String: TimeZone]?>("setTimezone")
-}
-```
-
-#### Migration steps
-
-1. Create a `TimeZoneBridge` which conforms to `Defaults.Bridge` and its `Value` is `TimeZone` and `Serializable` is `[String: String]`.
-
-```swift
-private struct TimeZoneBridge: Defaults.Bridge {
-	typealias Value = TimeZone
-	typealias Serializable = [String: String]
-
-	func serialize(_ value: TimeZone?) -> Serializable? {
-		guard let value else {
-			return nil
-		}
-
-		return [
-			"id": value.id,
-			"name": value.name
-		]
-	}
-
-	func deserialize(_ object: Serializable?) -> TimeZone? {
-		guard
-			let object,
-			let id = object["id"],
-			let name = object["name"]
-		else {
-			return nil
-		}
-
-		return TimeZone(
-			id: id,
-			name: name
-		)
-	}
-}
-```
-
-2. Create an extension of `TimeZone` that conforms to `Defaults.NativeType` and its static bridge is `TimeZoneBridge`. The compiler will complain that `TimeZone` does not conform to `Defaults.NativeType`. We will resolve that later.
-
-```swift
-private struct TimeZone: Hashable {
-	var id: String
-	var name: String
-}
-
-extension TimeZone: Defaults.NativeType {
-	static let bridge = TimeZoneBridge()
-}
-```
-
-3. Create an extension of `CodableTimeZone` that conforms to `Defaults.CodableType`.
-
-```swift
-private struct CodableTimeZone {
-	var id: String
-	var name: String
-}
-
-extension CodableTimeZone: Defaults.CodableType {
-	/**
-	Convert from `Codable` to native type.
-	*/
-	func toNative() -> TimeZone {
-		TimeZone(id: id, name: name)
-	}
-}
-```
-
-4. Associate `TimeZone.CodableForm` to `CodableTimeZone`
-
-```swift
-extension TimeZone: Defaults.NativeType {
-	typealias CodableForm = CodableTimeZone
-
-	static let bridge = TimeZoneBridge()
-}
-```
-
-5. **Call `Defaults.migrate(.timezone, to: .v5)`, `Defaults.migrate(.arrayTimezone, to: .v5)`, `Defaults.migrate(.setTimezone, to: .v5)`, `Defaults.migrate(.dictionaryTimezone, to: .v5)`**.
-6. Now `Defaults[.timezone]`, `Defaults[.arrayTimezone]` , `Defaults[.setTimezone]`, `Defaults[.dictionaryTimezone]` should be readable.
-
-**See [DefaultsMigrationTests.swift](./Tests/DefaultsTests/DefaultsMigrationTests.swift) for more example.**
diff --git a/readme.md b/readme.md
index a936902..6e326e4 100644
--- a/readme.md
+++ b/readme.md
@@ -434,17 +434,6 @@ Execute the closure without triggering change events.
 
 Any `Defaults` key changes made within the closure will not propagate to `Defaults` event listeners (`Defaults.observe()` and `Defaults.publisher()`). This can be useful to prevent infinite recursion when you want to change a key in the callback listening to changes for the same key.
 
-#### `Defaults.migrate(keys..., to: Version)`
-
-```swift
-Defaults.migrate<T: Defaults.Serializable & Codable>(keys..., to: Version)
-Defaults.migrate<T: Defaults.NativeType>(keys..., to: Version)
-```
-
-Type: `func`
-
-Migrate the given keys to the specific version.
-
 ### `@Default(_ key:)`
 
 Get/set a `Defaults` item and also have the SwiftUI view be updated when the value changes.