[jraph]

UA detection in the backend has also been frawned upon, it's not limited to code running in the browser.

And a proxy/CDN should not be doing something else than proxying requests and serving files.

Workarounds are fine, but that's what they are.

[fiedzia]

To get it working client-side you'd need to change the app, while the whole premise here is that you don't have to (and often can't). One point tracking what UA string are here and what they need is better than expecting every app author to handle this properly.