Title: Drop-ins
Author: WordPress VIP Documentation
Published: September 26, 2023
Last modified: January 1, 2024

---

 1. [WordPress on VIP](https://docs.wpvip.com/wordpress-on-vip/)
 2. Drop-ins

#  Drop-ins

Drop-ins are files designed to replace, add, or enhance specific WordPress Core 
features.

A limited set of drop-ins are provisioned for all WordPress environments on the 
VIP Platform by [VIP MU plugins](https://docs.wpvip.com/vip-go-mu-plugins/):

 * `db.php`: Adds [Automattic’s HyperDB database class](https://github.com/Automattic/HyperDB).
 * `object-cache.php`
 * `sunrise.php`: Customers can [modify `sunrise.php`](https://docs.wpvip.com/multisites/sunrise-php/)
   by creating and editing a `client-sunrise.php` file in their [application’s wpcomvip GitHub repository](https://docs.wpvip.com/wpcomvip-github-repository/).

No other drop-ins can be added to a WordPress site. If a drop-in is added to an 
application’s GitHub repository, it will be ignored by the environment.

[The Automattic-authored Maintenance Mode plugin](https://docs.wpvip.com/restricting-site-access/maintenance-mode/)
is the suggested alternative to the commonly used `maintenance.php` drop-in.

Last updated: January 01, 2024