[Standard] Stacks - Mainnet & Testnet - Upgrade to v4.0.2

Scheduled for Aug 24, 00:00 - 04:00 UTC

Scheduled

We are upgrading our Stacks Mainnet infrastructure to v4.0.2. This is a bugfix and improvement release focused on more consistent block production, reduced memory usage in the Clarity VM, and improved error reporting.

During the maintenance window, brief interruptions to RPC availability may occur.

RPC Changes:
- /v2/contracts/call-read — Status code for contract calls exceeding memory limits has changed from 408 to 400.
- /v3/contracts/fast-call-read — Status code for contract calls exceeding memory limits has changed from 408 to 400.
- POST /v2/stackerdb/

//chunks — Error responses now include dedicated error codes: ChunkTooBig and TooManySlotWrites, replacing the generic DataAlreadyExists for chunk-replacement failures.

https://github.com/stacks-network/stacks-core/releases/tag/4.0.2

Posted Aug 13, 2026 - 15:15 UTC

This scheduled maintenance affects: Stacks (Mainnet — REST API, Mainnet — Websockets API, Testnet — REST API, Testnet — Websockets API).