Arul Prasad J

This is a lightweight WordPress plugin that displays the current running PHP/MySQL version inside “At a Glance” admin dashboard widget.
Plugin uses standard actions and filters only. (No jQuery used)
If you love this plugin, <a href="https://paypal.me/arulprasadj?locale.x=en_GB" rel="nofollow ugc">buy me a cup of coffee</a>

WP PHP Version Display

Displays the current running PHP/MySQL version inside "At a Glance" admin dashboard widget.

antonroos

Display information about your WordPress, PHP, Web Server and MySQL installation. You only have to active the plugin and that is it. The information will show in your footer area in the admin section.
<h3>1.0.1</h3>
New in 1.0.1 
– You can now see your theme version and name in the footer.

Roosium Info

Display WordPress, PHP, Web Server, MySQL and Theme versions in wp-admin footer.

WP PHP Version Display vs Roosium Info