[redserk]

You contradicted yourself.

Whether you want to call it a “restriction”, “a lack of permission without being X type of activity”, or “it works because the app exhibits Y behavior”, it’s all functionally a restriction.

You can run some background activities that are not audio apps, but you’re at the mercy of iOS’s decision to keep your task active or not. If you’re off the charger, all bets are off. iOS’s dev docs make this very clear.

[lostmsu]

No, basic set theory: not every restriction is a fundamental restriction.

[redserk]

Elaborate?

[lostmsu]

I said NOT(rule in "fundamental restrictions") AND (rule is XXX). You showed (XXX in "restrictions"). It would have been sufficient to prove my statement false if "fundamental restrictions" === "restrictions", but it is not.