iOS 更新可能非常令人兴奋。它们不仅具有改进 iPhone 功能的惊人功能，而且大多数增量更新还包含大量修复程序，可解决已知错误和问题。
然而，iOS 的 beta 版本并非如此。它们通常会破坏关键功能、阻止应用程序正常运行或导致与电池相关的问题。在极少数情况下，您也可能会在稳定的 iOS 版本中遇到这种情况。
如果您已经用尽了所有其他故障排除选项（您是否尝试过重置您的 iPhone(resetting your iPhone)？），那么降级 iOS 可能会有所帮助。
降级 iOS 的工作原理
根据您是在 iOS 的 beta 版还是稳定版，以下是降级 iPhone 系统软件的工作原理：
- 通过将 iPhone 恢复到恢复模式，您可以从 iOS 的 Beta 版本降级到最新且稳定的系统软件版本。这并不复杂，您可以随时进行操作。
- 您可以通过使用IPSW(IPSW)（iPod软件(Software)）文件恢复 iPhone，从稳定版本的 iOS 降级到另一个稳定版本。Apple在新版本发布后的几天或几周内停止“签署”（或验证）旧 iOS 版本。在大多数情况下，这使得除了系统软件的先前迭代之外无法返回任何内容。如果错过时间窗口，则无法降级。
降级 iPhone（从 beta 版或稳定版）也将删除您的所有数据(erase all your data)。这包括应用程序、设置、文档、照片、消息、联系人等。
如果您有来自即将降级到的相同（或更早）iOS 版本的 iCloud 或Finder/iTunes备份，您可以通过之后恢复来取回数据。您还可以将某些形式的同步数据（例如照片和信息）检索到 iCloud，只需使用您的Apple ID登录即可。
但是，降级的 iPhone 将不接受在较新版本的 iOS 上创建的备份(a downgraded iPhone will not accept a backup created on newer versions of iOS)。例如，您不能使用 iOS 14.3 中的 iCloud 或 Finder/iTunes 备份来恢复 iOS 14.2 上的数据。您也不能在 iOS 14.3 的稳定版本上使用来自 iOS 14.4 测试版的备份。
如果您没有任何较旧的备份，恢复数据的唯一方法是create a new Finder/iTunes backup并使用涉及编辑备份的 PLIST 文件的解决方法(use a workaround that involves editing the backup’s PLIST file)。您可以在下面进一步阅读所有相关信息。也就是说，如果您最终丢失数据，我们不承担任何责任。
如何将 iOS Beta降级到 iOS 稳定版
将 iPhone 从 beta 版本降级到 iOS 的稳定版本（例如从 iOS 14.0 beta 到 iOS 13.7 或从 iOS 14.4 beta 到 iOS 14.3）非常简单。但是，您无法选择要降级到的版本。
1.通过USB将您的 iPhone 连接到您的 PC 或Mac。
2. 打开Finder或 iTunes 并选择您的 iPhone。
3.强制重启你的 iPhone 并进入恢复模式(enter recovery mode)。
4.在 Finder 或 iTunes 中选择恢复。(Restore )
5. 选择恢复和更新(Restore and Update)以确认您要继续。
6. 同意许可条款。
7.等待(Wait)Finder/iTunes完成将稳定版 iOS 下载到您的Mac或 PC。根据您的互联网连接速度，可能需要几分钟到一个小时才能完成。
重要提示：(Important:)如果您的 iPhone 在下载过程中退出恢复模式（它会在 15 分钟后自动退出），请等待下载完成并将其重新置于恢复模式。然后，重复步骤4 – 6。
Finder/iTunes完成下载更新文件后，您的Mac或 PC 将自动开始恢复您的 iPhone。收到“您的 iPad 已恢复出厂设置...”消息后，选择确定(OK)。但是，在您看到 iPhone 上的“Hello”屏幕之前不要断开连接。
如何将 iOS稳定(Stable)版降级到以前的(Previous) 稳定(Stable)版
将 iPhone 从稳定版本降级到较早的稳定版本可能会稍微复杂一些。对于初学者，您必须使用Mac(Mac)或 PC下载系统软件IPSW文件的签名版本。然后，您必须使用 Finder/iTunes 从下载的文件中恢复您的 iPhone。
1. 打开 iPhone 上的设置(Settings)应用程序。然后，转到Apple ID > Find My > Find My iPhone并禁用Find My iPhone。
2.在您的 Mac 或 PC 上访问IPSW.me。
3. 选择您的 iPhone 型号。然后，选择要降级到的 iOS 签名版本。如果您没有看到签名版本（除了您当前使用的版本），则无法降级。
4. 下载IPSW系统软件文件。
5.通过USB将您的 iPhone 连接到您的计算机或(USB)Mac。
6. 打开Finder或 iTunes 并选择您的 iPhone。
7. 按住Option (Mac) 或Shift (PC) 并选择恢复 iPhone(Restore iPhone)按钮。
8. 选择下载的IPSW文件。然后，选择打开(Open)。
9. 选择恢复(Restore)。
您的Mac或 PC 将立即开始降级您的 iPhone。一旦您遇到“您的 iPad 已恢复到出厂设置...”弹出消息，请选择确定。(OK )但是，在看到“Hello”屏幕之前不要断开 iPhone。
如何从iCloud 或 Finder/iTunes备份中恢复您的(Backup)数据(Data From)
降级 iOS 后，您可以使用兼容的 iCloud 或Finder/iTunes备份来恢复数据。设置 iPhone 时，在应用程序(Apps)和数据屏幕上选择(Data)从 iCloud 备份(Restore from iCloud Backup)恢复或从 Mac 或 PC 恢复，(Restore from Mac or PC)然后按照屏幕上的所有说明恢复数据。
由于您无法使用在较新版本的 iOS 上创建的 iCloud 或Finder/iTunes备份来恢复数据，因此以下解决方法应该可以帮助您。但是，它仅限于Finder/iTunes备份。
1.为您的Mac或 PC下载PLIST编辑器。这里有几个建议：
Mac： BB编辑(BBEdit)
PC： plist Editor Pro
2. 转到您计算机上包含Finder/iTunes备份的文件夹。
Mac：打开 Finder，按Command + Shift + G，复制下面的路径，然后选择Go：
~Library/Application Support/MobileSync/Backup
PC：按Windows + R打开Run，复制下面的路径，然后选择OK：
%USERPROFILE%/Apple Computer/MobileSync/Backup
如果目录不存在，请改用以下路径：
%APPDATA%/Apple Computer/MobileSync/Backup
3. 选择 iPhone 备份文件夹。
4.在 PLIST 编辑器中找到并打开Info.plist 。
5. 找到标有Product Version的行。按Cmd + F或Ctrl + F并使用PLIST编辑器的Find功能更快地到达线路。
6. 在Product Version行下，将 iOS 版本号替换为降级 iOS 版本的版本号。例如，如果您刚刚降级到 iOS 14.2，请将其添加为版本号。
7. 按Cmd + S或Ctrl + S保存更改。然后，退出PLIST编辑器。
您现在可以从备份中恢复。返回 iTunes 或Finder。然后，选择您的 iPhone，使用“从此备份恢复”(Restore from this backup)旁边的菜单选择备份，然后选择“继续(Continue)” 。
进展如何？
降级iOS并不难。您对要降级到的版本别无选择。尽管如此，除非您在 iPhone 上不断遇到严重问题，否则没有理由首先这样做。仅将降级作为最后的手段。
如果您有任何问题，请发表评论，我们将尽力为您提供帮助。
How to Downgrade iOS
iOS updates can be incredibly exciting. Not only do thеy come with amazing features that improve the functionality of your iPhone, but most incremental updates also contain loads of fixes that resolve known bυgs and issues.
That isn’t the case with the beta versions of iOS, however. They often break down key features, prevent apps from running properly, or cause battery-related problems. On rare occasions, you may experience that with stable iOS releases as well.
If you’ve exhausted all other troubleshooting options (have you tried resetting your iPhone yet?), then downgrading iOS is a likely move that can help.
How Downgrading iOS Works
Depending on whether you’re on the beta or the stable channel of iOS, here’s how downgrading the iPhone’s system software works:
- You can downgrade from a beta release of iOS to the most recent—and stable— version of the system software by restoring your iPhone in recovery mode. It’s not complicated and you can do that whenever you want.
- You can downgrade from a stable release of iOS to another stable version by restoring your iPhone with an IPSW (iPod Software) file. Apple stops ‘signing’ (or authenticating) older iOS versions within a few days or weeks of a new release. In most cases, that makes it impossible to go back to anything other than the previous iteration of the system software. If you miss the time window, you can’t downgrade.
Downgrading an iPhone (from a beta or a stable release) will also erase all your data. That includes apps, settings, documents, photos, messages, contacts, and so on.
If you have an iCloud or a Finder/iTunes backup from the same (or an earlier) iOS version that you are about to downgrade to, you can get your data back by restoring from it afterward. You can also retrieve certain forms of synced data to iCloud—such as photos and messages—simply by signing in with your Apple ID.
However, a downgraded iPhone will not accept a backup created on newer versions of iOS. For example, you can’t use an iCloud or Finder/iTunes backup from iOS 14.3 to restore your data on iOS 14.2. Nor can you use backups from the beta release of iOS 14.4 on a stable release of iOS 14.3.
If you don’t have any older backups, the only way to get your data back is to create a new Finder/iTunes backup and use a workaround that involves editing the backup’s PLIST file. You can read all about it further below. That said, we do not accept any responsibility if you end up losing your data.
How to Downgrade iOS Beta to iOS Stable
Downgrading an iPhone from a beta release to a stable version of iOS (such as from iOS 14.0 beta to iOS 13.7 or iOS 14.4 beta to iOS 14.3) is quite straightforward. You can’t pick the version that you want to downgrade to, however.
1. Connect your iPhone to your PC or Mac via USB.
2. Open Finder or iTunes and select your iPhone.
3. Force-restart your iPhone and enter recovery mode.
4. Select Restore in Finder or iTunes.
5. Select Restore and Update to confirm that you want to go ahead.
6. Agree to the license terms.
7. Wait for Finder/iTunes to finish downloading the stable version of iOS to your Mac or PC. Depending on the speed of your internet connection, it may take several minutes to an hour to complete.
Important: If your iPhone exits recovery mode during the download (which it automatically will after 15 minutes), just wait for the download to complete and put it back into recovery mode. Then, repeat steps 4–6.
After Finder/iTunes finishes downloading the update file, your Mac or PC will automatically begin to restore your iPhone. Once you receive a “Your iPad has been restored to factory settings…” message, select OK. However, do not disconnect until you see the “Hello” screen on the iPhone.
How to Downgrade iOS Stable to a Previous Stable Version
Downgrading an iPhone from a stable version to an earlier stable build can be slightly complicated. For starters, you must download a signed version of the system software IPSW file using your Mac or PC. You must then use Finder/iTunes to restore your iPhone from the downloaded file.
1. Open the Settings app on your iPhone. Then, go to Apple ID > Find My > Find My iPhone and disable Find My iPhone.
2. Head over to IPSW.me on your Mac or PC.
3. Select your iPhone model. Then, select the signed version of iOS that you want to downgrade to. If you don’t see a signed release (other than the version that you’re currently on), you can’t downgrade.
4. Download the IPSW system software file.
5. Connect your iPhone to your computer or Mac over USB.
6. Open Finder or iTunes and select your iPhone.
7. Hold down Option (Mac) or Shift (PC) and select the Restore iPhone button.
8. Select the downloaded IPSW file. Then, select Open.
9. Select Restore.
Your Mac or PC will start to downgrade your iPhone immediately. Select OK once you come across the “Your iPad has been restored to factory settings…” pop-up message. However, do not disconnect your iPhone until you see the “Hello” screen.
How to Restore Your Data From an iCloud or Finder/iTunes Backup
After downgrading iOS, you can restore your data using a compatible iCloud or Finder/iTunes backup. While setting up your iPhone, select Restore from iCloud Backup or Restore from Mac or PC on the Apps & Data screen and follow all on-screen instructions to get your data back.
Since you can’t restore your data using an iCloud or a Finder/iTunes backup created on a newer version of iOS, the following workaround should help you out. However, it’s limited to Finder/iTunes backups only.
1. Download a PLIST editor for your Mac or PC. Here are a couple of suggestions:
Mac: BBEdit
PC: plist Editor Pro
2. Go to the folder that contains the Finder/iTunes backup on your computer.
Mac: Open Finder, press Command+Shift+G, copy the path below, and select Go:
~Library/Application Support/MobileSync/Backup
PC: Press Windows+R to open Run, copy the path below, and select OK:
%USERPROFILE%/Apple Computer/MobileSync/Backup
If the directory doesn’t exist, use the following path instead:
%APPDATA%/Apple Computer/MobileSync/Backup
3. Select the iPhone backup folder.
4. Locate and open Info.plist in a PLIST editor.
5. Locate the line labeled Product Version. Press Cmd+F or Ctrl+F and use the PLIST editor’s Find functionality to get to the line faster.
6. Under the Product Version line, replace the iOS version number with that of the downgraded iOS release. For example, if you just downgraded to iOS 14.2, add that as the version number.
7. Press Cmd+S or Ctrl+S to save the change. Then, exit the PLIST editor.
You can now restore from the backup. Go back to iTunes or Finder. Then, select your iPhone, pick the backup using the menu next to Restore from this backup, and select Continue.
How Did It Go?
Downgrading iOS isn’t hard. You just have no choice over the version that you want to downgrade to. Still, there’s no reason to do that in the first place unless you keep running into serious issues on your iPhone. Only perform a downgrade as a last resort.
If you have any questions, drop in a comment and we’ll try our best to help you out.
