Does this only apply to UI changes? Or can i fix, say, a logic bug as well?

Also, what kind of performance concerns might I see?

You don't "fix" anything, unless by "fix" you mean "turn off broken feature". It's a nice idea, too bad they tout it with such deceptive marketing.

Hm, I hadn't thought it would be misleading and asked for feedback on the heading. I guess the people I asked for feedback already know how it works... Thanks for telling me this because we consider ourselves super straight-shooting and want to be clear. We'll improve.

I believe it works using their Visual Apptimizer, which means that it's only UI changes atm.

As for performance, i've seen no issues.

An example is hiding Facebook login. You can unhide it later (also without resubmitting) when you're ready to put it back.

That's really a misleading - almost bullshit-level - description.

More accurately, you can 'remotely disable features so, if you shipped something broken, you can turn it off'.

You're being almost misleading using phrasing like you can 'fix iOS bugs live'. You can disable parts of your implementation. That's quite a bit different.

Stop trying to mislead the biz side of the house that doesn't know any better.

Our users call it a hotfix so that's what we're calling it. Often the fix is something they do on the server side while they disable the frontend. Does that make sense? It's not meant to be misleading but succinct headlines are hard to write.