Update the iPhone 6s plus loudspeaker to another newer apple like 8

hypothetically, you could do it by jumping the leads to the traces under the device with some thin wires.

they are not designed to be interchanged between the models modularily, so you will need a solderhing skillset to do this.

Please keep in mind, i have never personally done this, as custom modification work is not allowed at our franchise, so i will be unable to assist you if you run into trouble with the procedure. there could be issues with Voltage ratings, and the like.