new droplet still with Ubuntu 14.04.4 LTS

Hi there,

We tried to upgrade the ubunta server from the current 14.04.4 to 16.04. the version is correct once log back in after a restart but don’t know why the php wasn’t automatically updated to 7.0. then we did a manual php upgrade to 7.0 which appeared to be successful. however, none of our wordpress websites works and got the following instead. I guess some of the php files are missing. We followed an advice on https://www.digitalocean.com/community/questions/upgraded-ubuntu-on-droplet-now-wordpress-site-is-blank but still in vain. Any idea?

<?php
/**
 * Front to the WordPress application. This file doesn't do anything, but loads
 * wp-blog-header.php which does and tells WordPress to load the theme.
 *
 * @package WordPress
 */

/**
 * Tells WordPress to load the WordPress theme and output it.
 *
 * @var bool
 */
define('WP_USE_THEMES', true);

/** Loads the WordPress Environment and Template */
require( dirname( __FILE__ ) . '/wp-blog-header.php' );

besides, then we followed the recommendation on https://www.digitalocean.com/community/questions/should-i-do-release-upgrade-to-16-04-2-lts by spinning up a new droplet and migrated the snapshot droplet to the new one (https://www.digitalocean.com/community/tutorials/how-to-migrate-digitalocean-droplets-using-snapshots). however, the ubunta, php and mysql are still the old ones. Isn’t it true that all the newly created droplets have the latest ubunta, php and mysql installed? If not, how can we install the latest ubunta, php and mysql versions?

Thanks in advance.

tom