The Bitcoin development community has released Bitcoin Core v31.0, the latest major update to the reference implementation of the Bitcoin protocol, and it brings significant improvements that touch on three critical areas of Bitcoin’s technical infrastructure: mempool management, privacy, and node performance. The Bitcoin Core v31.0 upgrade represents years of careful development work by the open-source contributor community, and its implications for how Bitcoin transactions are processed, priced, and propagated across the network are meaningful for everyone from individual Bitcoin users to major institutional participants running full nodes. Understanding what Bitcoin Core v31.0 changes — and what those changes mean in practice — is essential context for anyone serious about Bitcoin’s long-term technical trajectory.

What Is Bitcoin Core and Why Does Bitcoin Core v31.0 Matter?

Bitcoin Core is the open-source software that implements the Bitcoin protocol and runs on the majority of Bitcoin full nodes globally. When you run a Bitcoin full node — a computer that independently verifies every transaction and block on the Bitcoin blockchain without trusting any third party — you are almost certainly running Bitcoin Core. The health, security, and performance of the Bitcoin network therefore depends significantly on the quality of Bitcoin Core software, and major releases like Bitcoin Core v31.0 represent carefully reviewed, community-tested improvements to this critical infrastructure.

Bitcoin Core v31.0 follows a development process that is intentionally conservative and deliberate, reflecting the enormous stakes involved in making changes to software that secures hundreds of billions of dollars in value. Bitcoin Core upgrades go through extensive peer review, testing, and debate before inclusion in a release, which means that the features included in Bitcoin Core v31.0 have been vetted far more rigorously than typical software updates. The April 2026 release of Bitcoin Core v31.0 is therefore not a routine software update but a carefully considered set of improvements that the Bitcoin development community has collectively judged to be safe, beneficial, and ready for broad deployment.

The Mempool Redesign in Bitcoin Core v31.0

The most technically significant change in Bitcoin Core v31.0 is the redesigned mempool — the pool of unconfirmed transactions waiting to be included in a block by miners. The mempool in previous versions of Bitcoin Core had a number of efficiency limitations that became more apparent as Bitcoin transaction volumes grew and fee markets became more sophisticated. The Bitcoin Core v31.0 mempool redesign addresses these limitations through several key improvements that collectively make fee estimation more accurate, transaction propagation more efficient, and miner revenue optimisation more effective.

The Bitcoin Core v31.0 mempool redesign introduces improved cluster mempool tracking, which groups related transactions (parent-child chains of unconfirmed transactions) together and evaluates their collective fee rates rather than individual transaction fees. This change is particularly important for multi-transaction workflows like Lightning Network channel opens and closes, PSBT-based multi-signature transactions, and complex smart contract-like constructions built using Bitcoin Script. By evaluating transaction clusters holistically, Bitcoin Core v31.0 enables more accurate fee estimation for complex workflows and helps ensure that miners select the highest-fee transaction clusters rather than just the highest individual transaction fees.

The practical implication of the Bitcoin Core v31.0 mempool redesign for Bitcoin users is improved fee estimation accuracy. One of the most frustrating experiences for Bitcoin users has historically been transactions that get stuck in the mempool during periods of high network congestion because their fees were set too low based on inaccurate fee estimates. The Bitcoin Core v31.0 improvements should reduce the frequency of this problem by providing more precise information about the fee landscape, allowing wallets and applications that use Bitcoin Core’s fee estimation to calibrate transaction fees more accurately and avoid unnecessary delays or overpayments.

Mandatory Tor and I2P Privacy in Bitcoin Core v31.0

Another significant change in Bitcoin Core v31.0 is the expansion and strengthening of privacy features related to how Bitcoin nodes connect to each other and broadcast transactions. Previous versions of Bitcoin Core supported optional Tor and I2P connectivity for nodes that wanted to hide their IP addresses and protect the privacy of their transaction broadcasting. Bitcoin Core v31.0 makes significant changes to how these privacy-preserving network overlays are integrated, moving toward a model where privacy protections are more deeply embedded in the default node behaviour rather than purely optional add-ons.

The Bitcoin Core v31.0 privacy improvements address a longstanding concern in the Bitcoin community: network-level surveillance. When a Bitcoin node broadcasts a new transaction, it initially propagates it to its connected peers, and a sufficiently resourced adversary — such as a government intelligence agency or a sophisticated analytics firm — can in principle identify which node first broadcast a transaction, potentially linking that node’s IP address to the transaction sender. This type of network surveillance does not require breaking Bitcoin’s cryptographic security; it simply requires monitoring the Bitcoin peer-to-peer network at scale and observing the timing of transaction propagation. The Bitcoin Core v31.0 enhancements to Tor and I2P integration make this type of surveillance significantly harder by better obscuring the origin node of transactions.

Node Performance and Scalability Improvements

Beyond the mempool redesign and privacy enhancements, Bitcoin Core v31.0 includes a range of performance improvements that make running a full Bitcoin node faster, less resource-intensive, and more practical on a wider range of hardware. Initial block download (IBD) — the process a new node goes through when first syncing the entire Bitcoin blockchain from genesis — has been optimised in Bitcoin Core v31.0 through improved database access patterns and better parallelisation of verification tasks. These IBD improvements reduce the time and disk I/O required to bootstrap a new node, which is particularly important for encouraging more users to run full nodes and thereby strengthening Bitcoin’s decentralisation.

Memory usage optimisations in Bitcoin Core v31.0 also make it more practical to run a full node on hardware with limited RAM. As the Bitcoin blockchain has grown to hundreds of gigabytes, the memory requirements for validation have increased, and some users running nodes on older hardware have struggled with memory pressure during peak activity periods. Bitcoin Core v31.0’s memory optimisations help ensure that the population of users who can run a full node remains as broad as possible — an important consideration for Bitcoin’s long-term decentralisation, since a network with millions of full nodes is far more resistant to censorship and capture than one with only thousands.

What Bitcoin Core v31.0 Means for Miners

The Bitcoin Core v31.0 mempool improvements have direct implications for Bitcoin miners, who select transactions from the mempool to include in blocks and earn the associated transaction fees. The cluster mempool improvements in Bitcoin Core v31.0 allow miners using this software to more efficiently identify the most profitable set of transactions to include in a block, potentially increasing their fee revenue relative to miners using older software with less sophisticated mempool management. While the improvement in any individual block may be small, across thousands of blocks the cumulative revenue difference can be meaningful, providing miners with a financial incentive to upgrade to Bitcoin Core v31.0 promptly.

The miner revenue optimisation improvements in Bitcoin Core v31.0 also have positive implications for Bitcoin network security. Miner revenue from transaction fees is an increasingly important component of Bitcoin’s long-term security model as the block subsidy (newly minted Bitcoin rewarded to miners per block) continues to decline through successive halving events. Each Bitcoin halving reduces the block subsidy by 50%, and Bitcoin Core v31.0’s improvements to transaction fee collection efficiency help ensure that the fee market that will eventually need to fully support network security is as efficient and fair as possible.

How to Upgrade to Bitcoin Core v31.0

For Bitcoin node operators and developers wanting to upgrade to Bitcoin Core v31.0, the process is straightforward for most users. Bitcoin Core v31.0 is available for download from bitcoincore.org and is compatible with all major operating systems including Linux, macOS, and Windows. Node operators should verify the cryptographic signatures on the downloaded software before installation to ensure they are running authentic Bitcoin Core v31.0 code and not a tampered version. The Bitcoin Core v31.0 release includes detailed release notes documenting all changes, migration guides for users with custom configurations, and instructions for backing up wallet data before upgrading.

For users running Bitcoin nodes on consumer hardware or Raspberry Pi-based node packages like Umbrel, myNode, or RaspiBlitz, upgrade paths to Bitcoin Core v31.0 will be provided through each platform’s standard update mechanism. These managed node platforms typically release Bitcoin Core v31.0 compatible updates within days to weeks of the official Bitcoin Core release, after performing their own integration testing. Node operators who have set up custom Bitcoin Core installations will need to upgrade manually, following the instructions in the Bitcoin Core v31.0 release documentation.

Conclusion: Bitcoin Core v31.0 Strengthens Bitcoin’s Foundation

Bitcoin Core v31.0 represents the Bitcoin development community’s continued commitment to steadily improving the technical foundation that secures the world’s most valuable cryptocurrency. The mempool redesign improves fee estimation and miner revenue efficiency. The enhanced Tor and I2P privacy protections make Bitcoin more resistant to network surveillance. The performance improvements make running a full node more accessible to a wider range of users and hardware. Together, these changes in Bitcoin Core v31.0 make Bitcoin modestly but meaningfully better across several dimensions that matter for long-term health and adoption. In a market cycle where Bitcoin is testing $80,000 and institutional adoption is accelerating, Bitcoin Core v31.0 is a timely reminder that Bitcoin’s strength rests not just on market dynamics but on the continuous, careful work of its open-source development community to maintain and improve the protocol that underpins it all.