App updates are not downloading from Caching Server on iOS 10.3.3 and below

Originator:DieselG5
Number:rdar://6468254618 Date Originated:8/1/2017
Status:Open Resolved:
Product:macOS Server Product Version:5.3.1
Classification: Reproducible:Yes
 
Summary:
A caching server on 10.12.5 with Server 5.3.1 installed will not serve iOS app updates to devices running iOS 10.3.3 or below. It will, however, cache and serve apps (new installs only, not updates) and iOS updates.

If an iOS device running iOS 10.3.3 or below requests a new app from the app store, it is cached and served correctly. If it requests an update, the app update is downloaded from Apple. This has been tested on the below devices with their respective results:

iPad 3 - iOS 9.3.5: App updates do not download from caching server
iPhone 5S - iOS 10.3.3: App updates do not download from caching server
iPhone 6 - iOS 10.3.3: App updates do not download from caching server
iPhone 6S - iOS 10.3.3: App updates do not download from caching server

iPhone 6 - iOS 11b3: App updates download from caching server correctly

Steps to Reproduce:
1. Download app from app store on iOS device running iOS 10.3.3 or below and ensure it is downloaded on the caching server.
2. Wait for an update to be available and update from the app store. Check the log to see where the update is coming from.
2a. Delete the app and redownload it to ensure caching is working for new installs

Expected Results:
The iOS device should download app updates from caching server.

Actual Results:
Caching Server doesn't notice a request from the device and the device downloads the app update from Apple.

Version:
iMac (10.12.5) running Server.app (5.3.1)

Comments

Apps distributed via VPP on an MDM device use the caching server correctly for app updates on iOS 10.3.3 and below.


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