1 App Store

原文

While signed in with a production account and testing with a sandbox account, attempting to fetch a new valid receipt displays a sign-in prompt for the production account with no option for switching to the sandbox account. (42862150)
Workaround: For testing purposes, StoreKit calls such as making a purchase and restoring transactions will fetch a new receipt. Alternatively, sign out of the production account.

使用生产帐户登录并使用沙盒帐户进行测试时，尝试获取新的有效收据会显示生产帐户的登录提示，但不能选择切换到沙盒帐户。（42862150）
解决方法：出于测试目的，StoreKit调用（例如进行购买和恢复事务）将获取新收据。 或者，退出生产帐户。

2 Core Graphics

原文

Various Core Graphics calls have been hardened against continuing with invalid parameters. In iOS 12, these calls may now return nil or return early. (38344690)

各种核心图形调用已经过强化，无法继续使用无效参数。 在iOS 12中，这些调用现在可以返回nil或提前返回。（38344690）

3 Core ML

New Features
Support for quantized models (≤ 8-bit linear and/or lookup table)
Support for flexible image sizes and multi-array shapes
Batch prediction API
Support for custom models
Support for Create ML models (Vision Feature Print, Text Classifier, Word Tagger)

264/5000
新功能
支持量化模型（≤8位线性和/或查找表）
支持灵活的图像大小和多阵列形状
批量预测API
支持自定义模型
支持创建ML模型（Vision Feature Print，Text Classifier，Word Tagger）

4 HomeKit

Inviting iOS 11 users who have multiple email addresses associated with their Apple ID to a home might not succeed. (41033550)
Workaround: Send the invitation to a different email address or phone number associated with the Apple ID of the iOS 11 user.

邀请具有与其Apple ID相关联的多个电子邮件地址的iOS 11用户可能无法成功。（41033550）
解决方法：将邀请发送到与iOS 11用户的Apple ID关联的其他电子邮件地址或电话号码。

5 Maps

Traffic data might not be displayed. (43254370)
Workaround: Tap the Settings button (ⓘ) to reveal Maps Settings and toggle the Traffic switch on.

可能不会显示交通数据。（43254370）
解决方法：点击“设置”按钮（ⓘ）以显示“地图设置”并切换“交通”开关。

6 MediaPlayer Framework

When perform (queueTransaction:completionHandler:) is called on applicationqueueplayer to modify the position of a song, the queue returns unchanged. (39401344)

当在applicationqueueplayer上调用perform（queueTransaction：completionHandler :)来修改歌曲的位置时，队列返回不变。（39401344）

6 Networking

New Features
The URLSession HTTP/2 implementation supports HTTP/2 connection reuse per RFC 7540 Section 9.1.1. This requires an HTTP/2 server to present a certificate which covers more than one server hostname. The certificate may use the Subject Alternative Name extension or wild-carded domain names. In addition, URLSession requires name resolution to resolve the different hostnames to the same IP address. URLSession may reuse HTTP/2 connections across different domain names when these conditions are satisfied. (37507838)
Deprecations
FTP and File URL schemes for Proxy Automatic Configuration (PAC) are deprecated. HTTP and HTTPS are the only supported URL schemes for PAC. This affects all PAC configurations including, but not limited to, configurations set via Settings, System Preferences, profiles, and URLSession APIs such as connectionProxyDictionary, and CFNetworkExecuteProxyAutoConfigurationURL(::::). (37811761)

新功能
URLSession HTTP / 2实现支持RFC 7540第9.1.1节中的HTTP / 2连接重用。 这要求HTTP / 2服务器提供涵盖多个服务器主机名的证书。 证书可以使用主题备用名称扩展名或通配符域名。 此外，URLSession需要名称解析才能将不同的主机名解析为同一IP地址。 当满足这些条件时，URLSession可以在不同域名之间重用HTTP / 2连接。
弃用
不推荐使用代理自动配置（PAC）的FTP和文件URL方案。 HTTP和HTTPS是PAC唯一支持的URL方案。 这会影响所有PAC配置，包括但不限于通过设置，系统首选项，配置文件和URLSession API（如connectionProxyDictionary）和CFNetworkExecuteProxyAutoConfigurationURL（::: :)设置的配置。

6 Phone and FaceTime

Group FaceTime has been removed from the initial release of iOS 12 and will ship in a future software update later this fall.
In iOS 12, Camera Effects in Messages is available only on iPhone SE and iPhone 6s or later and is unavailable on iPad. Camera Effects in FaceTime is available only on iPhone 7 or later and is unavailable on iPad.
Wi-Fi calls might end unexpectedly when transitioning from Wi-Fi to cellular while on the T-Mobile network. (39251828)

Group FaceTime已从iOS 12的初始版本中删除，并将在今年秋季晚些时候的未来软件更新中发布。
在iOS 12中，“消息中的相机效果”仅适用于iPhone SE和iPhone 6s或更高版本，并且在iPad上不可用。 FaceTime中的相机效果仅适用于iPhone 7或更高版本，并且在iPad上不可用。
当在T-Mobile网络上从Wi-Fi转换到蜂窝时，Wi-Fi呼叫可能意外结束。（39251828）

7 Screen Time

The start and stop times for Downtime might change unexpectedly if they were configured prior to installing iOS 12 beta 9. (43393555)
Workaround: Update all devices associated with the iCloud account to the release version of iOS 12 and reset the start and stop times for Downtime.
After updating to iOS 12, parents should change the Screen Time passcode to prevent children from signing out of iCloud or changing the system time. (42879250)
“Picked Up Phone” statistics might be inflated due to data syncing from other devices signed into the same iCloud account. (39917173)

如果在安装iOS 12 beta 9之前配置了停机时间，则启动和停止时间可能会意外更改。（43393555）
解决方法：将与iCloud帐户关联的所有设备更新到iOS 12的发行版，并重置停机时间的开始和停止时间。
更新到iOS 12后，家长应更改屏幕时间密码，以防止孩子退出iCloud或更改系统时间。（42879250）
由于登录到同一iCloud帐户的其他设备的数据同步，“Picked Up Phone”统计信息可能会膨胀。（39917173）

8 Siri

• When using INUIAddVoiceShortcutButton, the “Add to Siri” and “Added to Siri” button text isn’t localized. (43251696)
  Workaround: To localize “Add to Siri” and “Added to Siri” button text, include localizations for this text in the strings files of your app bundle.
• While multiple ride-sharing apps are installed, Siri might open the app instead of providing an ETA or location when asked. (42324032)
  Workaround: Ask Siri for the ETA or location again.
• Siri Shortcuts might not work if a device is locked. (41307405)
• Siri Suggestions for Shortcuts are enabled on iPhone 6s or later, iPad Pro, iPad (5th generation or later), iPad Air 2, and iPad mini 4. (40669231)

*使用INUIAddVoiceShortcutButton时，“添加到Siri”和“添加到Siri”按钮文本未本地化。（43251696）
解决方法：要本地化“添加到Siri”和“添加到Siri”按钮文本，请在应用程序包的字符串文件中包含此文本的本地化。
虽然安装了多个乘坐共享应用程序，但Siri可能会打开应用程序，而不是在被问到时提供ETA或位置。（42324032）
解决方法：再次询问Siri的ETA或位置。
如果设备被锁定，Siri快捷方式可能无效。（41307405）
在iPhone 6s或更高版本，iPad Pro，iPad（第5代或更高版本），iPad Air 2和iPad mini 4 \上启用Siri建议的快捷方式。（40669231）

9 UIKit

You might encounter issues with systemLayoutSizeFitting(_:) when using a UICollectionViewCell subclass that requires updateConstraints(). (42138227)
Workaround: Don’t call the cell’s setNeedsUpdateConstraints() method unless you need to support live constraint changes. If you need to support live constraint changes, call updateConstraintsIfNeeded() before calling systemLayoutSizeFitting(_:).

使用需要updateConstraints（）的UICollectionViewCell子类时，可能会遇到systemLayoutSizeFitting（_ :)的问题。（42138227）
解决方法：除非需要支持实时约束更改，否则不要调用单元格的setNeedsUpdateConstraints（）方法。 如果需要支持实时约束更改，请在调用systemLayoutSizeFitting（_ :)之前调用updateConstraintsIfNeeded（）。

10 USB Accessories

To improve security, iOS 12 may require you unlock your passcode-protected iPhone, iPad, or iPod touch in order to connect it to a Mac, PC, or USB accessory.
If you use iPod Accessory Protocol (iAP) USB accessories over the Lightning connector (such as CarPlay, assistive devices, charging accessories, or storage carts) or you connect to a Mac or PC you might need to unlock your device to recognize the accessory. If you don't unlock your device, it won't communicate with the accessory or computer, and it won't charge. Note that you don't need to unlock your device to charge using an Apple USB power adapter.
If a USB accessory isn't recognized after you unlock your device, disconnect it, unlock your device, and reconnect the accessory.
If you normally use a USB assistive device to enter your passcode, you may allow it to communicate with your device while it is locked by enabling “USB Accessories” in Settings > Face ID/Touch ID & Passcode.

为了提高安全性，iOS 12可能会要求您解锁受密码保护的iPhone，iPad或iPod touch，以便将其连接到Mac，PC或USB附件。
如果您使用Lightning接口上的iPod附件协议（iAP）USB配件（例如CarPlay，辅助设备，充电配件或存储车）或连接到Mac或PC，则可能需要解锁设备才能识别附件。 如果您没有解锁设备，它将无法与配件或计算机通信，也不会充电。 请注意，您无需使用Apple USB电源适配器解锁设备即可充电。
如果解锁设备后无法识别USB配件，请断开连接，解锁设备，然后重新连接配件。
如果您通常使用USB辅助设备输入密码，则可以通过在设置>面部识别/触摸ID和密码中启用“USB附件”来允许其在设备锁定时与您的设备进行通信。

11 Xcode

When using Messages in the iOS Simulator, a message might not be delivered from User A to User B. (40916530)
Workaround: Send a message from User B to User A.

在iOS模拟器中使用消息时，可能无法从用户A向用户B发送消息。（40916530）
解决方法：从用户B向用户A发送消息。

12 Foundation

主要修改分类：

Secure Data Archival and Unarchival

Secure Value Transformer

NSSecureCoding Conformance

Macro for Closed Enumerations

UserDefaults

On-Demand Resources

Thread Safety of Bundles

CFMessagePort

详情见：
Foundation