Scheduled maintenance is currently in progress. We will provide updates as necessary.
Posted Mar 31, 2026 - 23:00 UTC
Scheduled
We are upgrading our Stacks Mainnet nodes to 3.4.0.0.0, implementing consensus version 3.4 which activates at Bitcoin block 943,333 (estimated April 2, 2026). This is a required upgrade; nodes not upgraded before activation will require a full genesis sync to rejoin the network. During the maintenance window, brief interruptions to RPC availability may occur.
## RPC Changes
**`at-block` Clarity keyword — removed** New contracts referencing `at-block` are rejected at static analysis. Existing deployed contracts that invoke `at-block` will fail at runtime with an `AtBlockUnavailable` error.
**Transaction events for post-condition aborted transactions — removed** The EventDispatcher no longer emits transaction events when transactions abort due to post-condition failures. Downstream consumers (APIs, indexers, analytics) that relied on these events will need to adjust accordingly.
**`/v3/blocks/simulate/{block_id}` and `/v3/block/replay` — modified** These simulation and replay endpoints no longer emit transaction events for post-condition aborted transactions. Callers expecting events from failed transactions will receive incomplete results.