Remove old iPhone from Find My after replacement?

If your old iPhone was lost or stolen, do not remove it from Find My. Removing it will turn off Activation Lock and allow anyone who has the device to use it.

1. Open Find My ➡️ Devices ➡️ select the old iPhone.

2. If the device is lost or stolen, tap Mark As Lost and leave it on your account.

3. Only tap Erase This Device and Remove This Device if you physically have the old iPhone or it was returned to you.

Axel F.

Don't remove the device from Find My, even if you remotely erase it. Removing the device from your Find My list removes Activation Lock, which will make it easier for the thief to unlock and resell your device. - https://support.apple.com/120837

Follow the instructions here: https://support.apple.com/guide/icloud/remove-a-device-mmfc0eeddd/1.0/icloud/1.0