Sagepay plugin issue

Hi, Hope you are well

I just integrated the Sagepay plugin with my eCommerce site but whenever any visitor from Ipv6 comes to my site he/she is not able to complete the payment as this plugin only supports Ipv4 customers for payment.
Can anyone help me or let me know how I can make changes in this plugin so that my ipv6 customers can also send payments thanks.

Waiting for help

thanks
Jenny South