Bitcoin Core 32 is entering its final testing phase, bringing a collection of under-the-hood changes to one of the most widely used pieces of Bitcoin infrastructure. The update is set to modify fee estimation, block processing and wallet behavior without changing Bitcoin’s underlying rules.
The first release candidate for Bitcoin Core 32.0 was tagged on September 14. According to the project’s release schedule, developers are targeting October 10 for the finished version.
For most Bitcoin users, this will be invisible. The changes are aimed primarily at the software running behind the scenes: the nodes that independently verify transactions and blocks instead of trusting an outside service.
The result is less about changing what Bitcoin is and more about making the machinery around it respond more efficiently.
One notable change concerns transaction fees. Bitcoin Core currently estimates fees largely by examining transactions that were included in earlier blocks, meaning recent congestion can continue influencing recommendations even after the network starts to clear.
Version 32 introduces a second estimator that examines transactions still waiting in the mempool. The software will compare the two approaches and can recommend the lower fee when network conditions justify it.
That could make fee recommendations adjust more quickly after periods of congestion, rather than continuing to reflect transactions that were confirmed when fees were higher.
Bitcoin Core 32 Is Tuning the Machinery Behind Bitcoin
Block validation is also getting a performance boost. Nodes will be able to retrieve transaction data from their databases across multiple processing threads while checking blocks.
Bitcoin Core will use eight threads by default for this process. The change is designed to reduce the amount of time a node spends waiting for information stored on disk, particularly while catching up with the blockchain.
The release also addresses a security flaw that had been present since Bitcoin Core 24.0 on non-Windows systems.
Under specific conditions, an authenticated user with permission to create wallets could use a specially crafted wallet name to trigger commands on the computer hosting the node. The attack depended on the operator having enabled walletnotify, a feature that automatically executes a selected command when wallet transactions occur.
Bitcoin Core 32 changes the behavior so wallet names are treated as literal text rather than allowing parts of those names to be interpreted as commands.
The update also changes how several commands handle partially signed Bitcoin transactions. Four commands used to create PSBTs will default to PSBT version 2, a newer format commonly used when transactions move between wallet software and signing devices before being finalized.
Older PSBT versions remain available when explicitly requested, but applications built directly around those Core commands will need to account for the new default.
Then there is the web server.
Bitcoin Core 32 replaces the existing server used by other applications to communicate with a node. During testing, an audit of the replacement server using Moonshot AI’s Kimi K3 model identified a memory-exhaustion problem.
The issue came from the server continuing to accept data from a client while it was still processing an earlier request. That data could accumulate in memory faster than the software could clear it, potentially driving memory usage higher and higher.
The problem was found before the new server reached a stable Bitcoin Core release, allowing developers to fix it ahead of version 32’s wider deployment.
Testing found a similar issue in Bitcoin Core’s REST interface, which can be accessed without login credentials. In one test, 16 unauthenticated REST connections pushed a node’s memory use from 46 MB to roughly 3 GB in about a minute.
In a 90-second test, the unfixed version consumed 3.2 GB of memory. After the fix, usage was about 3 MB.
Bitcoin Core 32 is therefore arriving with a distinctly practical agenda: make nodes faster at processing blockchain data, make fee estimates more responsive and close security gaps before they become bigger problems.
None of that changes Bitcoin’s consensus rules. Instead, the release is refining the software that helps thousands of computers independently enforce them.