> ## Documentation Index
> Fetch the complete documentation index at: https://docs.chainstack.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Chainstack updates: July 18, 2024

> zkSync Era Mainnet support is added on Chainstack, and customers can now apply discount promo codes when changing their subscription plan in billing.

* **Protocols**. zkSync Era Mainnet support.
* **Billing**. When changing your subscription plan, you can now use promo codes with discounts to a plan's regular price.