How to replace entry title heading tag for a specific Featured Post widget using GFPC.

functions.php

// Change h2 markup to h1 for a specific GFPC widget
add_filter( 'gfpc_do_post_title_gfpc-widget-5', 'sk_custom_title', 10, 2 );
function sk_custom_title( $title, $instance ) {

	$replace = 'h2';
	$replace_with = 'h1';

	$title = str_replace( $replace, $replace_with, $title );

	return $title;

}