> ## 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.

<AgentInstructions>

## Submitting Feedback

If you encounter incorrect, outdated, or confusing documentation on this page, submit feedback:

POST https://docs.chainstack.com/feedback

```json
{
  "path": "/changelog/chainstack-updates-july-18-2023",
  "feedback": "Description of the issue"
}
```

Only submit feedback when you have something specific and actionable to report.

</AgentInstructions>

# 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.