If you want to implement custom field support for Frontier Post, you you can now do this by adding code to your functions.php in your child theme – Below example adds a Rating field:

Custom fields requires fairly advanced php and WordPress skills. Custom fields will not be supported, unless there is a bug in the Frontier Post code – In other words, I cannot support your custom code.

Updated February 2017

//***************************************************************************************
//* Add custom fields to Frontier Post
//***************************************************************************************


// ********* Text field - Buttom of form *******

function fp_my_custom_text_field( $thispost, $tmp_task_new) 
	{
	// New table cell containing additional fields
	echo '<tr><td class="frontier_no_border">';
	echo '<fieldset class="frontier_post_fieldset_additional">';
	echo '<legend>Additional fields</legend>';
	
	// a table to hold the fields and ensure alignment
	echo '<table class="frontier_no_border"><tr>';
		
		
		// Simple text field	
		$simple_txt_fld = get_post_meta( $thispost->ID, 'fp_text_fld', true );
		echo '<td class="frontier_no_border">Text field:</td>';
		echo '<td class="frontier_no_border">';
		echo '<input name="fp_text_fld" id="fp_text_fld" value="'.$simple_txt_fld.'" size="40" type="text">';			
		echo '</td>';
	echo '</tr></table>';
	echo '</fieldset>';
	echo '</td></tr>';
	}
	
// add the action	
add_action( 'frontier_post_form_standard_top', 'fp_my_custom_text_field', 10, 2 );



// ********* Rating field - Buttom of form *******

function fp_my_custom_rating( $thispost, $tmp_task_new) 
	{
	// New table cell containing additional fields
	echo '<tr><td class="frontier_no_border">';
	echo '<fieldset class="frontier_post_fieldset_additional">';
	echo '<legend>Additional fields</legend>';
	
	// a table to hold the fields and ensure alignment
	echo '<table class="frontier_no_border"><tr>';
		
		// rating field		
		$rating = intval(get_post_meta( $thispost->ID, 'fp_rating', true ));
		echo '<td class="frontier_no_border">Rating:</td>';
		echo '<td class="frontier_no_border">';
			$tmp_html = '<select class="frontier_post_dropdown" name="fp_rating" id="fp_rating" >';
			$tmp_html .= '<option  value="0"'.($rating == 0 ? ' selected="selected" >' : '>').'Not rated</option>';
			// Build from 1 to 5 star rating
			for ($i = 1; $i <= 5; $i++)
				{
				$tmp_html .= '<option  value="'.$i.'"'.($rating == $i ? ' selected="selected" >' : '>').$i.' Stars</option>';
				}
		
			$tmp_html = $tmp_html.'</select>';
			echo $tmp_html;
		echo '</td>';	
		
	echo '</tr></table>';
	echo '</fieldset>';
	echo '</td></tr>';
	}
	
// add the action	
add_action( 'frontier_post_form_standard', 'fp_my_custom_rating', 10, 2 );

// *** End display frontier post custom fields

//***************************************************************************************
//* Get custom field values, and save them
//***************************************************************************************

function fp_save_my_custom_fields($tmp_post, $tmp_task_new, $input_values )
	{
	
	// Rating
	if ( array_key_exists('fp_rating', $input_values) )
		{
		update_post_meta($tmp_post->ID, 'fp_rating', intval($input_values['fp_rating']) );
		}
		
	// Text Field
	if ( array_key_exists('fp_text_fld', $input_values) )
		{
		update_post_meta($tmp_post->ID, 'fp_text_fld', $input_values['fp_text_fld'] );
		}
	
	}
add_action( 'frontier_post_post_save', 'fp_save_my_custom_fields', 10, 3 );
// ** End save Frontier Post Custom fields **