Do I need to calibrate a new replacement iPhone 11 battery?

There was a bug in iOS 14.4 that broke capacity reporting, that was fixed iOS 14.5 but required re-calibrating the battery gauge (not the battery) after it was installed This was automatic, and required no action on the part of the user. As long as your iOS version is higher than 14.5 you are OK. This may be where you heard about recalibrating with the iPhone 11.

Hi! By “calibrate,” do you mean like, manually draining and recharging the battery in a particular pattern, or are you seeing a battery-related notification in Settings after the replacement?

To confirm, just in case: there’s no special manual drain-to-zero-charge-to-100% routine after you replace an iPhone 11 battery.

if you’re thinking the iPhone 11’s automatic battery-health recalibration system, that happens on its own in the background, and you don’t need to do anything.

Tell me this: if you go to Settings > Battery > Battery Health & Charging or Settings > General > About > Parts & Service History, what does it say? Is there a warning or anything?

No, if you bought a genuine Apple battery that was installed by the Apple Store / Genius Bar or an authorized Apple service shop.

All bets are off if you purchased a third party battery, since it is unlikely to work correctly with the battery settings on the iPhone.