From Newsgroup: comp.mobile.ipad

PSA:
The only practical way to preserve iOS apps
(including IPAs, app data, and sub-versions)
is to keep a spare iOS device in your desk drawer,
(a different iOS device for each archive)
so you can archive to and from it at a later date
(e.g., if you buy a new iPhone 17 & you want all the old
app sub versions and all your app data and settings).

Don't blame me for the steps since this is how Apple does things.

DEFINITIONS:
IPA = the packaged app program downloaded from the App Store
(similar to a ZIP)
App bundle = the installed form of the IPA after iOS unpacks it
App data = our documents, settings, saved progress
App sub-version = the specific version of the app installed on the device

Note that Android & Windows separate the installer from the installed app.
a. APK (Android) is an installer, not the installed app.
b. MSI/EXE (Windows) is an installer, not the installed program.

But iOS does NOT separate the installer from the installed program, per se.
a. We download an IPA.
b. iOS unpacks it into an app bundle.
c. The bundle is the installed app.
d. The original IPA file is deleted after installation.

So on iOS, the installed app bundle is the unpacked IPA.

Note iCloud backups do NOT include the IPA or the installed app bundle.
Neither do computer-based backups include the IPA or the installed bundle.

They only save your app data.
During restore, iOS attempts to re-download the IPA from the App Store.
If the IPA is gone, abandoned, or incompatible, the app cannot be restored.

That's something only iOS does as no other common consumer operating system prevents a backup from containing the actual app installer (where, in the
case of Android, the app installer is *always* saved on the device itself).

Platform clarification:
a. On macOS: backups are made using Finder (or older iTunes versions).
b. On Windows: backups are made using iTunes.
c. On Linux: there is no official Apple backup tool
(so, for Linux, only iCloud backups apply)

In ALL cases above, backups save ONLY app data.
They NEVER save the IPA, the installed bundle, or the app sub-version.
Restore always depends on the App Store still offering the IPA.

But wait... there's more. Much more. There's a trick!

A powered-off, drawer-stored iOS device can act as an "app archive"!
Yup. How cool is that!

Since Quick Start device-to-device transfer copies:
a. the installed app bundle (the unpacked IPA, the actual runnable app),
b. the app data (your documents and settings),
c. the exact app sub-version installed on the old device
We can take advantage of this trick to archive installed iOS apps!

This is the ONLY Apple-supported method that preserves the runnable app
itself (i.e., the installed bundle) and the exact sub-version, and not just
the app data.

One way to create an iOS-app-archive device:
a. Power off and old iOS device and store it safely.
b. When you want to preserve your current device's apps and data,
turn on the archive device.
c. Use Quick Start to transfer from your current device
to the archive device.
d. Power off the archive device, and store it safely.

What this method preserves:
a. The installed app bundle (the unpacked IPA, the runnable app)
b. The app data (documents, settings, saved progress)
c. The exact app sub-version currently installed
d. Apps removed from the App Store
e. Old sub-versions that cannot be re-downloaded
f. Apps from developers who disappeared
g. Apps that still run on the old device's iOS version

What this method cannot guarantee:

This is not a perfect time capsule. It works only as long as:
a. The installed app bundle still runs on the old device
b. The app's sub-version is still compatible with the new
device's iOS version

If both conditions hold, Quick Start will continue to copy the installed bundle, the app data, and the exact sub-version even many years later.

In summary, this trick is needed if you actually want to archive the IPA.
But keep in mind the old device is not a "backup", per se.
It's more like a "living copy" of:
a. the installed app bundle (the unpacked IPA),
b. the app data,
c. the exact sub-version.

As long as that living copy still runs, it can be cloned forward into the future.

There are practical considerations:
1. The living archive should start clean
2. But it should be under your identity

Here's how to set up that living copy of you app archives.

1. Erase the device completely
Settings > General > Transfer or Reset iPad >
Erase All Content and Settings

2. Set it up as YOUR device
a. Sign in with YOUR Apple ID
b. Do NOT restore from anyone's backup
c. Choose 'Set Up as New iPad'

3. (Optional but important)
a. Update iOS to a version that:
i. Is new enough to run your current apps
ii. But not so new that it risks breaking any
very old apps you might want to preserve

4. Turn it into the archive
a. Use Quick Start from your current iPhone/iPad to this archive iPad
b. Let it copy:
i. your installed app bundles (unpacked IPAs),
ii. your app data,
iii. your exact app sub-versions

5. When done
a. Power it off
b. Put it in the drawer

Note if you wanted multiple versions over time, you would need multiple physical devices, one for each living archive. It's how Apple does things.

If you don't have multiple physical iOS devices to make multiple archives, then you must use the same device, but you can have only one archive.

6. To update the archive device again in the future
a. Turn on the archive device
b. Verify that it still boots and that the preserved apps still run
c. Place it next to your current device
d. Start Quick Start on your current device
and choose the archive device as the TARGET of the transfer
e. Allow it to copy:
i. the installed app bundles (unpacked IPAs),
ii. the app data,
iii. the exact app sub-versions
f. This overwrites the previous state of the archive device
with a new snapshot of your current device
g. When the transfer is complete, power it off
h. Put it back in the drawer

How to use the archive device when you buy a new iPhone 17.

1. Turn on the new iPhone 17
a. It should be at the "Hello" screen (unactivated)
b. Do NOT set it up manually
c. Do NOT sign in
d. Do NOT restore from iCloud or a computer

2. Turn on your archive device
a. Make sure it still boots
b. Make sure the preserved apps still run
c. Place it next to the new iPhone 17

3. Start Quick Start on the new iPhone 17
a. The new iPhone will detect the archive device
b. Choose "Transfer from iPhone"
c. The archive device becomes the SOURCE
d. The new iPhone 17 becomes the TARGET

4. Let Quick Start run
a. It will copy:
i. the installed app bundles (unpacked IPAs),
ii. the app data,
iii. the exact app sub-versions
b. This recreates your preserved environment on the new iPhone 17
c. No App Store downloads are required for preserved apps

5. When the transfer finishes
a. The new iPhone 17 now contains:
i. your preserved apps,
ii. your preserved sub-versions,
iii. your preserved app data
b. The archive device is unchanged
c. Power off the archive device and return it to storage

6. Continue using the new iPhone 17 normally
a. Install new apps
b. Update apps if you want
c. When we want to refresh the archive again in the future,
we repeat the archive-update procedure we already defined

If there is any other way to archive common consumer iOS apps without
using the App Store, I don't know it, so please let us all know.

This is the way Apple does things, so don't blame me for the steps.
--
On Usenet, old men with vast experience voluntarily share that knowledge.
--- Synchronet 3.21d-Linux NewsLink 1.2