Hi zacmaot,
Thanks for contacting Apple Support Communities!
We understand that you're seeing an alert that your iPhone battery isn't a genuine part.
This can happen if your iPhone battery isn't functioning properly as outlined here: About genuine iPhone batteries - Apple Support
"An Unknown Part
message will appear if the battery installation is incomplete or if the battery:
- Was replaced with a nongenuine battery
- Was already used or installed in another iPhone
- Isn't functioning as expected
An additional message might appear that says "Apple has updated the device information for this iPhone." This means that Apple has updated the device information maintained for this iPhone for service needs, safety analysis, and to improve future products.
These messages don't affect your ability to use your iPhone or your battery."
It sounds like your iPhone battery will require service. We'd suggest that you contact Apple directly to help you to determine what service options are available to you. You can find their contact details here: Contact Apple Support
Kind regards.
Learn more about iPhone parts and service history.