EDITS:

April 28, 2018

• /u/LEL-LAL-LOL claims this process works for iOS 11

• I constructed this guide from experimenting with an iPhone SE on 10.3.1

• I want to share that this guide was intended as a manual, offline method when archiving apps. Once the necessities are acquired, all processes can be done without internet access.

May 4th, 2018

• With help of, and claims by /u/LEL-LAL-LOL and /u/BlackStab_IRQ -- new, on-the-fly methods are now provided for Processes A, B, and C via "Apps Manager" and "Filza" which can also support iOS 11

• Separated Introduction and Prerequisites

• Changed !!CAUTION!! to !!ATTENTION!!, and added new information to !!ATTENTION!!

Introduction

Ever since iOS 9, Apple has applied some sort of restriction that prohibits iTools and similar PC iDevice managers from backing up .IPA files. This guide will walk you through the process of app restoration! There's additional steps to follow than when backing up from <iOS 8.x devices, but AFAIK it's the best alternative as of April 28th, 2018. Following this guide will allow users to maintain their app library archive. If there's ever a time you wanted to remove an app, but retain the data you've generated so far, (EG: game data or note-keeping) then this process can help you!

There is no particular order here with the guide. There's just four individual processes to follow with their own instructions. However, the guide is begins at Process A as if starting with nothing.

!!ATTENTION!!

This process has not been tested with...

• Cache data restored to a different version of its app other than its original version.
• iOS 11 (just iOS 9.x.x and iOS 10.x.x). [Refer to the edits]
• AppleTV (just iPhones, but I'm certain its the same as well for iPad/iTouch).
• Native Apple System apps.
• Following Method 2 for Processes B and C saves the cache data locally onto your iDevice via usage of Apps Manager. However, Method 1 for B and C allows it to be secured onto a computer due to a more manual, universal process. I say "universal" because when following Method 1, you'll be able to migrate data between iDevices; Method 2 is isolated to just that iDevice. As of May 4th, 2018, I am unsure where Apps Manager stores the cache data for extraction so I am unable to provide further assistance for that.
• Currently, there is no cross-support for Method 2 for Processes B and C, meaning if you'd do Method 2 for B and C; those steps aren't compatible with Method 1 for B and C.
  

Prerequisites

You'll need to have a few tools ready before proceeding. Please have:

"Apps Manager" (BigBoss), "Appster" (BigBoss), "Apple File Conduit 2" (Cydia), "Filza" (BigBoss), and "Ext3nder Installer" (repo: julioverne.github.io) installed.

Secondly, I used iTools as my choice for PC iDevice manager, but you're welcome to choose your own. The steps will be expressed generally to achieve the same results.

Process A - App Extraction

Method 1

• A1) Open Ext3nder Installer and access "More" from the bottom row.
• A2) Scroll down to "SHOW USER APPLICATIONS" and enable it.
• A3) Select "Installed" from the bottom row and you'll now see all user-installed apps appear.
• A4) Click the desired app and select "Rebuild To .IPA". This will backup the app to the: "/var/mobile/Documents/Ext3nder/" directory.

!! OR !!

Method 2 (Original instructions revised by me.)

• AX1) Using Apps Manager, select your app then scroll down to "Bundle" and click on the directory link (This will redirect you into Filza) !! OR !! Using Filza, access this directory: "/var/containers/Bundle/Application" and open your app's folder
• AX2) Inside your app's folder, create a new folder and name it "Payload". This can be done by pressing "Edit" > "More" > "New Folder"
• AX3) Select "Edit" again and select these objects: "BundleMetadata.plist", "iTunesMetadata.plist", and your "X.app" folder (X is your app's name).
• AX4) Copy and paste those selected files into the "Payload" folder. You'll have to go inside the "Payload" folder then paste.
• AX5) Go back one directory, hit "Edit", highlight "Payload", then "More", and "Create ZIP"
• AX6) Highlight the newly created "x.zip" and rename it to "XY.ipa", where XY is literally whatever you want to name the .IPA.
• AX7) You may now delete the previously created "Payload" folder

You've just now backed up the app! Using a PC, you can now pull the .IPA and secured it someplace safe! However its cache data is still not secured.

Process B - Cache Extraction

These next steps will lead where to go to backup and restore the apps' cache. Using a PC iDevice manager tool is recommended for ease. However using Filza can yield the same results.

Method 1 - Manual/PC Method

• B0) This is a prerequisite step if using a PC iDevice manager program. Please install "Apple File Conduit 2" if not already. This will allow your tool to access the jailbreak partition of your iDevice.
• B1) Using Appster, locate your app and select it. Scroll down to "BUNDLE" and view its "Folder" ID string and remember it.

(Author's Note: As of a discovery on June 9th, 2018, Appster does not provide Cache Directory, use Apps Manager instead. Run Apps Manager > select the app > click on 'Data'. This'll take you the app's cache folder where you'll see the ID under the app's title.)

• B2) Using either Filza or your PC program, access this directory, "/var/mobile/Containers/Data/Application/"; your app's cache will be located here. (Filza will list the name of the app here along with its ID.)
• B3) Select your app's folder ID and what you'll find inside are: "Documents", "Library", "tmp", "com.apple.mobile.XXX" (XXX are variables), etc. and possibly "StoreKit" -- depending on your apps. Copy all these files to a secured place.

!! OR !!

Method 2 - Apps Manager Method

• BX1) Using Apps Manager, select your app.
• BX2) Scroll down to "Backup" select it and confirm it.
• BX3) Apps Manager has now successfully backup your app's cache data.

Process C - Restoration

Method 1 - PC/Manual Method

• C1) Reinstall your app -- either through personal backup or AppStore. (Please ensure the AppStore's version matches your app cache's.) You don't need to launch it, but if you did already, you may be prompted to overwrite files later. (This step can be skipped if the app wasn't deleted after following step B1. Otherwise, re-installing the app will have its folder ID changed since then, so you'll have to refer back to Appster in step B1 to locate it again.)
• C2) Using either Filza or your PC program, access this directory, "/var/mobile/Containers/Data/Application/" and select your app's folder ID.
• C3) Paste back in the app cache.

!! OR !!

Method 2 - Apps Manager Method

• CX1) Perform Step C1 if you have havent't already reinstalled the app.
• CX2) Using Apps Manager, select "Backups" from the bottom row.
• CX3) Select your app, and you'll find a Date & Time entry of when the backup was made. (Following step BX2 would have produced one.)
• CX4) Apps Manager has now successfully restored your app's cache data.

And that's it! You've successfully restored the .IPA and its cache data!

Process D - Extracting "Contained records"

This is a special step for those who extracted apps from iDevices on iOS 8 or lower, but want their data migrated to a new iOS. Now the "Contained records" was a feature on iTools where backing up an .IPA also backed up the cache in one go. (It even included "Contained records" as a suffix to the .IPA filename.) So when restoring on <iOS 8, the app and cache was restored altogether. However, when trying to reinstall the same .IPA to iOS 9 or iOS 10, it'll fail the cache recovery. I'm uncertain if there were other programs like iTools that did this, so your experience may vary. This process assumes you already have your desired apps backed up from said feature.

You will need access to a PC or MAC and a compression program like WinZip, WinRAR, or 7zip. (I recommend 7zip due to its massive efficiency and format compatibility.)

• D1) Reveal file extensions. How-To for Windows and How-To for Mac.
• D2) On our computer desktop, duplicate your app by making a secondary copy to avoid accidental misuse.
• D3) Rename the app by adding a ".zip" at the end of its filename and confirm the change.
• D4) Using your compression program, open and inspect the newly converted .zip.
• D5) Access "Container" and copy out all of its contents. After, either rename the app back to .IPA or delete the copy if you made one.
• D6) Refer back to step C1.

Thanks for reading and hopefully this guide has helped you as much as its helped me! Enjoy!