From Newsgroup: comp.sys.mac.advocacy
Maria Sophia wrote:
Q: Was your IPA ever in any backup made by iTunes or Finder?
A: No.
Q: Why your IPA was never in any backup made by iTunes or Finder
A: This PSA explains a long standing misconception about iOS backups.
Many users erroneously believe that the IPA (i.e., the actual re-usable app installer) is included in (old) iTunes or Finder backups. This has never been true on any version of iOS, on any version of iTunes, on macOS Finder, or
on any other Apple backup mechanism.
Those people who believe that, are very confused about how iOS really works.
The confusion exists because the restore process makes it appear as if the IPA had been backed up. During a restore, iOS first restores the app's sandboxed data from the backup, and then the App Store server re-downloads the app binary. The user sees the app reappear and assumes the installer came from the backup. In reality, the IPA is fetched again from Apple's servers.
iOS backups contain only app data, not the app binary. The backup subsystem (BackupAgent) stores the app's Documents and Library directories, plus other data the app has marked as backup eligible. The IPA itself is never included. This has been the case since the first iPhone OS release.
Older versions of iTunes (before 12.7) did store IPA files on disk, but this was only because iTunes downloaded the IPA at the time of purchase or update. The IPA was never part of the iOS device backup. It was simply a local copy kept by iTunes. When Apple removed app management from iTunes, this local IPA storage disappeared, but the backup format did not change in this regard.
Modern iTunes on Windows and Finder on macOS behave the same way. They request a device backup from iOS, and iOS provides only app data, not the installer. The backup file set contains no IPA, no executable, and no app bundle. The restore process still re-downloads the app from the App Store.
This behavior is unique to Apple. Other operating systems do not delete or
hide the installer. Windows keeps the installer you downloaded. Android allows you to keep the APK. Linux package managers keep cached packages unless you explicitly purge them. Apple is the only major platform where the installer is never included in the backup and is not retained by the system.
The result is that if an app is removed from the App Store, you cannot restore it unless you already have a saved IPA from the old iTunes era or from a separate extraction method. The backup alone is not sufficient because it
never contained the IPA in the first place.
Summary: iOS backups have never included the IPA. iTunes never backed up the IPA. Finder never backed up the IPA. The restore process only re-downloads the app from Apple's servers and then applies the backed up data. The belief that the IPA was backed up is a misunderstanding caused by how seamless the restore process appears.
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