WordPress: Customize the admin footer

To be placed in the functions.php file:

function modify_footer_admin () {
echo 'Created by <a href="http://www.partitech.com">Partitech</a>.';
}
if (is_admin()) {
add_filter('admin_footer_text', 'modify_footer_admin');
}

Reproduce this customization today

The principle of the hook remains useful, but the administration screens and WordPress APIs have evolved since the publication. Test the code in a staging environment with the exact version of the site's core, theme, and plugins.

• Save the files and the database before making any changes.
• Control user capabilities, nonces, input validation, and output escaping.
• Place customizations in a dedicated plugin or a child theme to preserve updates.

Reference: official WordPress plugin development manual.