If you not heard about this problem then read my previous article that explains why you would see this message and the small chance it could affect you.
Apple changed their story
According to Apple, this error was never meant to "brick" your iPhone, and was only meant to be a diagnostic message for Apple only and then only within the factory or test facilities.
Sceptics might say the outcry and the obvious class action lawsuits that followed from more than a few law firms are unrelated to Apple now saying instead;
"That was on us, sorry about that".
If you were affected and still have your device then you can download an updated iOS that includes the fix. You will require the aid of a Windows or OS X based computer you can use and iTunes to restore your device.
If you ended up buying a new phone due to the "Out of Warranty" state of your device that Apple previous claimed - then you obtain a refund for that purchase.
If you are affected
If you see error 53 or can't update or restore your iPhone or iPad; then Apple has a support document to take you through the required steps.