Discovered from personal use then found it documented in app support notes. That's why iOS/iPadOS isn't a computer replacement.
https://docs.termius.com/faq/troubleshooting/cant-run-in-the-background
"Termius, like most of other apps, can’t run in the background
due to a restriction of iOS. The latest version of iOS stops the app’s background processes almost immediately (in 20 or 30 seconds), while older versions would allow them to run for 2 - 3 minutes."
interesting. I’m not a programmer and you’ve found something that matches your presumption by a specific application and developer that surmises other iOS apps in iOS 13 are restricted from background app processes. In my view, again I’m not a developer by any means, seems a bit like reality for filling its own prophecy here.
what I mean by this is the developer(s) in the link you’ve shown for Terminus - seemingly a powerful SSH client with command line tools for RDP sessions - yet even the developer does not specify what the exact restriction is - just background process. Yes I know I’m answering my own question here yet what I should state what I mean is what is the APIs that are used and/or restricting the app from running in the background.
seems there are 2 parties to this issue and one is pointing the blame on the other yet not telling teacher what events led to the action for blame.
Apple has a number of APIs centred around: Power (battery use), Performance, and Privacy as shown via their WWDC Developer sessions.
the use cases I’m able to find, potentially (I don’t know for certain here),could be based on these use cases:
Downloading & Uploading Files,
Periodic Updates,
New Server Data,
And possibly navigation.
It would seem that Terminus requires APIs that do not fall into the above category.
Background Processing Tasks,
Background App Refresh Tasks.
The 1st gives several minutes of processing time (at system friendly times; of course we don’t know how many background or foreground tasks are being run by a user at any given time so similar to Tron’s MCP calles CPU Monitor or CPUM for short is in charge here).
Due to this there is a specific note: “The system may choose to terminate your task early in case the system decides the conditions are no longer sufficient for you to run your task.”
terminus maybe one of those apps that is designed to be run all the time without regard to processor overload, power consumption or user privacy isn’t he background. It’s been designed for system admins or users that want background app all the time.
I think the way such an app is designed and thus restricted in one mobile OS vs another runs to the very core of the direction of each core OS. I feel it also runs over more than average users on Android who are unaware to check what services or system calls are running in the background using power or hogging memory and they don’t understand what’s going on since it’s not readily identifiable. Not I’m saying end user here in my surmise not the developer.
I’d like to see what interactions such developer had with Apple and their replies.
cheers