stacks-network/stacks-core 3.4.0.0.0

Release 3.4.0.0.0

on GitHub

This release implements the 3.4 Stacks consensus rules which activates at Bitcoin block 943,333.
For more details see the following SIPS:
SIP-039: Clarity 5 and Epoch 3.4
SIP-040: SIP for improved post-conditions
SIP-042: Removal of at-block

This is a required upgrade

• Activation is estimated for April 2, 2026 around 2000 UTC, or Bitcoin block 943,333.
• Upgrading after Bitcoin block 943,333 will require a genesis sync.

This release is compatible with chainstate directories from 3.3.x.x.x.

The version of stacks-signer compatible with this release is 3.4.0.0.0.0, available at: https://github.com/stacks-network/stacks-core/releases/tag/signer-3.4.0.0.0.0.

Added

• Set the epoch 3.4 activation height to 943,333 per SIP-039 and finalize all settings for epoch 3.4 and Clarity version 5.
• Added post-condition enhancements for epoch 3.4 (SIP-040): Originator post-condition mode (0x03) and NFT MAY SEND condition code (0x12), including serialization support and epoch-gated validation/enforcement.
• Disabled at-block starting from Epoch 3.4 (see SIP-042). New contracts referencing at-block are rejected during static analysis. Existing contracts that invoke it will fail at runtime with an AtBlockUnavailable error.

Changed

• /v3/blocks/simulate/{block_id} and /v3/block/replay no longer emit transaction events for post condition aborted transactions.
• EventDispatcher no longer emits transaction events for post condition aborted transactions.

Fixed

• Fixed signer database migration 19 that could leave the database in corrupted, unrecoverable state.