Fixing "WP_Widget is deprecated since version 4.3.0" Debug Message

Update wp-category-archive.php…

change line 32 from
function WP_Category_Archive_Widget()
to:
function __construct()

and line 38 from:
$this->WP_Widget(“wp-category-archive”, “Category Archive”, $widget_ops);
to:
parent::__construct(“wp-category-archive”, “Category Archive”, $widget_ops);

https://wordpress.org/plugins/wp-category-archive/