The wording of the prohibition has varied over the years. Current wording is:
Except as set forth in the next paragraph, an Application may not download or install executable code. Interpreted code may only be used in an Application if all scripts, code and interpreters are packaged in the Application and not downloaded. The only exceptions to the foregoing are scripts and code downloaded and run by Apple's built-in WebKit framework or JavascriptCore, provided that such scripts and code do not change the primary purpose of the Application by providing features or functionality that are inconsistent with the intended and advertised purpose of the Application as submitted to the App Store.
So even if you download JavaScript code and run it on Apple's VM, they reserve the right to reject it if it changes the primary purpose of the application.
I think that wording with the "exception" is from the OSX developer program. As far as I can remember, the iOS info sheet has always been taxative with no exceptions about executable code. Of course all wordings allow Apple to start rejecting a previous approved app if they feel the code/scripts the app is now downloading are in violation.
The explanation in the rollout.io site about why they are fine is intentionally deceptive. They have the guts to link to a document that says "An Application may not download or install executable code." and then quote more friendly excerpts in the hopes that you won't read the actual doc. I can't imagine why Apple has let this go on for so long.
>The only exceptions to the foregoing are scripts and code downloaded and run by Apple's built-in WebKit framework or JavascriptCore, provided that such scripts and code do not change the primary purpose of the Application by providing features or functionality that are inconsistent with the intended and advertised purpose of the Application as submitted to the App Store.
It looks like this says "If you use download code that is run on JavaScript core (ie, JavaScript), then you can do this so long as you don't change the purpose of your app when you submitted it to the App Store."
Except as set forth in the next paragraph, an Application may not download or install executable code. Interpreted code may only be used in an Application if all scripts, code and interpreters are packaged in the Application and not downloaded. The only exceptions to the foregoing are scripts and code downloaded and run by Apple's built-in WebKit framework or JavascriptCore, provided that such scripts and code do not change the primary purpose of the Application by providing features or functionality that are inconsistent with the intended and advertised purpose of the Application as submitted to the App Store.
So even if you download JavaScript code and run it on Apple's VM, they reserve the right to reject it if it changes the primary purpose of the application.