Bitcoin Core v32.0 defaults to PSBTv2, ships October 10
In brief
- Bitcoin Core v32.0rc1 tagged September 14; final release October 10
- PSBTv2 becomes default for four RPCs; deprecated fields removed
- Transaction index compression halves disk space but breaks backward compatibility
- HTTP server rewrite enforces stricter header handling and connection limits
- Downgrade to older versions triggers multi-hour index rebuilds
Protocol and RPC Changes
Bitcoin Core v32.0rc1 shifts four RPCs to default to PSBTv2, while other interfaces remove deprecated fields or reject arguments that older versions tolerated. This tightening of input validation closes gaps but forces wallet and exchange operators to test against the new baseline.
The change cascades across the ecosystem. Apps relying on lenient parsing will error on v32.0 nodes. Operators running mixed-version infrastructure face coordination risk if some instances upgrade before others.
Infrastructure Improvements
The most significant performance gain comes from parallel prefetching of transaction outputs during block connection. The feature defaults to eight worker threads and supports up to 16, accelerating initial block download and validation.
The HTTP server underwent a complete rewrite. It now enforces an 8,192-byte header limit, applies stricter malformed-header handling, caps RPC connections at 16 by default, adds new REST cache controls, and immediately disconnects unauthorized clients. These changes improve security but may break custom monitoring or load-balancing setups.
Storage and Backward Compatibility
The rebuilt transaction index uses less than half the disk space of the prior format—a major win for full-node operators. The catch: older releases cannot read the new index format. Downgrading from v32.0 to an earlier release will trigger a full index rebuild lasting hours.
Fee Estimation and Private Relay
The default estimatesmartfee path now combines block-policy and mempool estimators. This hybrid approach may return a lower fee estimate than either component alone and can error if either component fails—a behavioral shift that affects wallet UX.
For privacy-focused operators, v32.0 includes a Tor fallback fix and adjusts private-broadcast failure paths around a 10,000-entry queue and 1,000-attempt limit. Relay behavior under load also shifts.
The release does not signal a new consensus-rule activation. Bitcoin Core version 31.1 remains the current baseline, giving users time to stage the upgrade. One change tied to draft BIP 323 alters how the software treats signaling bits and unknown-deployment warnings.
