Plugin deprecated

Hi,

I try to install your plugin but I have this error message:

Notice: The called constructor method for WP_Widget is deprecated since version 4.3.0! Use

__construct()

instead. in …..\wp-includes\functions.php on line 3457

There is any actualisation?
How can I do to solve this.

Thank you for any help

https://www.ads-software.com/plugins/responsive-mortgage-calculator/