Software that controls your body should always respect your freedom. This article is a recap of scandals of medical devices, like hearing aids, insulin pumps, bionic eyes, and pacemakers, and what we can learn from them. It’s astonishing: you wouldn’t expect these devices to be run by software in such a way that they can leave you completely helpless.
Keeping a life critical device up to date sounds necessary, to the contrary.
Not if the existing software functions properly. If there’s a fix in it you need then sure, once the vendor has tested and approved it you should migrate.