Call to undefined function is_wp_version_compatible()

Hi

Version 1.7.1 of the plugin causes an error on our WordPress 4.9.15 installation. It appears to the call to the function is_wp_version_compatible() on line 36 of wp-ajaxify-comments.php is the cause.

According to Code Reference on is_wp_version_compatible the function was only added in WordPress 5.2.0.

Maybe you need to put this in a function_exists call to avoid the error?

If you need any more information, don’t hesitate to get in touch.

And thanks for your great plugin!