Make page numbering show in upper roman for all Gravity PDF documents

gravitypdf.php

<?php

add_filter( 'gfpdf_mpdf_class_config', function( $config ) {
	$config['defaultPageNumStyle'] = 'upper-roman';

	return $config;
} );

add_filter( 'gfpdf_mpdf_class_config', function( $config, $form, $entry, $settings ) {
	
	if ( $form['id'] === 1 ) {
		$config['defaultPageNumStyle'] = 'upper-roman';
	}

	return $config;
}, 10, 4 );