Iphone xs max update ios 15.1

Thanks.

Note the message which reads, “This update requires at least 50% battery or to be connected to a power source.”

Based only on your screenshot, your phone appears to be NEITHER.

What iOS are you running now?

How much available storage space do you have?

Are you on a “solid” WiFi connection to the internet?

What errors or messages do you receive when you try?

(it cerainly SHOULD update)