daviddunnington

function wc_custom_upsell_sorting() {
	woocommerce_upsell_display( - 1, 4, 'menu_order', 'ASC' );
}
remove_action( 'woocommerce_after_single_product_summary', 'woocommerce_upsell_display', 15 );
add_action( 'woocommerce_after_single_product_summary', 'wc_custom_upsell_sorting', 15 );

daviddunnington

function filter_woocommerce_get_stock_html( $html, $product ) {
	if ( $product->stock_status == 'outofstock' ) {
		$html .= 'Add custom HTML here';
	}
	return $html;
} 
add_filter( 'woocommerce_get_stock_html', 'filter_woocommerce_get_stock_html', 10, 2 );