> ## 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: September 30, 2026

> On Arbitrum, Base, Arc, and Robinhood Chain, MEV protection is renamed to Optimized Submission.

**Add-ons**. On Arbitrum, Base, Arc, and Robinhood Chain, MEV protection is renamed to [Optimized Submission](/docs/optimized-submission). Nodes that had MEV protection enabled now have Optimized Submission enabled.