Prevent WordPress update nag in custom WordPress plugins and themes using the Update URI header

As the WordPress Plugin and Theme repositories are growing the names of custom plugins and themes are running out. What if you create a theme or plugin with a name that’s already used in the WordPress repository? In that case, WordPress will ask you to update it, and that could lead to disastrous events.

Since WordPress 5.8 we have the Update URI header for plugins. When this is set – either to a URL, slug or simply to false – the WordPress API will not return any information for updates.

The update for themes is ready, but not yet integrated to WordPress Core. It’s likely that this will be integrated before 2023. The current status is discussed in #14179.

Examples of Plugin Headers with Update URI:

<?php
/*
Plugin Name: Your Plugin Name
Plugin URI: https://example.test
Description: The description of your plugin
Version: 1.0
Author: the author
Author URI: https://example.test
Update URI: false
*/

More information about support for Update URI in WordPress 5.8 is found on the link below:

https://make.wordpress.org/core/2021/06/29/introducing-update-uri-plugin-header-in-wordpress-5-8/