Bitcoin Core Update v32.0rc1 Introduces Compatibility Challenges for Wallets and Services

The Bitcoin Core v32.0rc1 update, tagged with a verified signature on September 14, has initiated a critical testing phase for node operators and wallet providers. This version is not a production-final upgrade but rather a candidate that could lead to temporary disruptions across popular applications relying on Bitcoin Core's RPC interfaces.

With the final release targeted for October 10, the 26-day window serves as a concentrated compatibility test. Changes in this release include alterations to how Bitcoin Core handles signaling bits and unknown-deployment warnings, although the proposal remains in draft status. Operators are encouraged to utilize the latest testing guide to evaluate the candidate against the previous release, focusing on commonly used features in separate temporary data directories.

One of the most significant performance changes in the draft release is the introduction of parallel prefetching of transaction outputs during block connection, which can enhance block processing speed. However, this feature can also introduce complexities regarding CPU, memory, and storage-latency costs.

Wallet and service integrations face additional risks as four RPCs will default to PSBTv2, while deprecated fields will be removed or rejected. Teams involved in transaction processing must carefully trace these changes to ensure compatibility with downstream parsers and signers.

Moreover, the update includes a rewritten HTTP server that expands the test surface, introducing stricter handling of malformed headers and connection limits. These changes may affect reverse proxies and health checks, necessitating thorough testing to confirm expected behaviors.

As the final tag remains a goal rather than a certainty, operators must pay attention to potential edge cases and prepare for the implications of the new transaction index format, which could complicate downgrades.