Would your plugin work on a site with PHP 8.1?

Hello! When I am trying to pay via gateway I have an error API_KEY / SECRET_KEY ARE NOT ALLOWED FROM THIS IP.
Can you help me to solve this problem?

My client has your PayPlus plugin for WooCommerce installed on his site. Someone else installed it 3 or 4 years ago and the plugin screen indicates version 3.0.9, yet your WordPress page indicates that your plugin was updated 3 days ago (April 13, 2021) to version 1.0.9.

1) Why are the version numbers conflicting (normally a new update would be a higher number, for example, 3.0.9 might update to 3.1.0)?

2) Why isn’t there an option inside of the WordPress Plugins screen (or anywhere in the WooCommerce screens such as the Manage screen for your plugin) to click to update your plugin?

3) I was not able to locate instructions to safely (without losing history) update your plugin manually or automatically anywhere on your website or in this WordPress Plugin information screen. Please provide instructions.