As the Bitcoin network navigates the final week of April 2026, the protocol finds itself at its most significant technical and philosophical crossroads since the block size wars. With the release of Bitcoin Core v31.0rc4 and the formal introduction of Bitcoin Improvement Proposal 361 (BIP-361), developers and stakeholders are grappling with a “Quantum Migration” plan that could fundamentally alter the network’s immutability in the name of long-term security.
By Marcus Johnson | April 24, 2026
The stability of the Bitcoin network has reached unprecedented levels in 2026, with the total network hashrate officially crossing the 1 Zetahash (ZH/s) threshold earlier this month. However, beneath the surface of this computational dominance lies a growing anxiety regarding the future of cryptographic security. April 24, 2026, marks a pivotal moment in this evolution as the community debates the implementation of a phased migration to quantum-resistant signature schemes—a move that includes a controversial provision to “freeze” legacy addresses that do not transition within a specific timeframe.
Bitcoin Core v31: The Cluster Mempool Revolution
The immediate technical focus for node operators this week is the testing of Bitcoin Core v31.0rc4. This version represents a massive architectural overhaul, most notably through the introduction of the “Cluster Mempool.” For over a decade, Bitcoin’s mempool—the waiting area for unconfirmed transactions—operated under a topology-limited structure that often struggled with fee estimation during periods of high congestion.
The new Cluster Mempool redesign organizes transactions into bounded groups, or “clusters,” limited to 64 transactions or 101 KB in total size. This change allows miners to create more efficient block templates and provides users with far more accurate fee projections. This is particularly critical for the maturation of the Lightning Network, where timely channel closures depend on precise fee placement. Beyond the mempool, v31 also introduces Tor-Only Broadcasting, a privacy feature that allows nodes to broadcast transactions exclusively through Tor or I2P, effectively blinding chain analysis firms that have historically used IP-to-transaction mapping to de-anonymize users.
BIP-361 and the “Quantum Migration” Strategy
While Core v31 focuses on immediate efficiency, the introduction of BIP-361, authored by a group of researchers including Jameson Lopp, addresses the existential threat posed by future quantum computing. Although practical quantum attacks on ECDSA (the Elliptic Curve Digital Signature Algorithm) are still theoretical, the “harvest now, decrypt later” strategy employed by state actors has prompted developers to act sooner rather than later.
BIP-361 outlines a multi-year roadmap for transitioning Bitcoin’s security architecture to post-quantum cryptography (PQC). The proposal is built on several key pillars:
- Phase A: The introduction of new quantum-resistant output types based on Winternitz One-Time Signatures (WOTS+) and SPHINCS+ algorithms.
- Phase B: A mandatory five-year “Migration Window” during which users must move funds from legacy P2PKH and P2WPKH addresses to the new quantum-secure formats.
- Phase C: The controversial “Freezing Clause,” which would render any unmigrated legacy outputs unspendable after the five-year grace period.
The Satoshi Clause: Immutability vs. Security
The most explosive aspect of the BIP-361 debate centers on the fate of nearly 2 million BTC currently held in legacy “lost” or “zombie” addresses. This includes the estimated 1.1 million BTC attributed to Satoshi Nakamoto. Under the current wording of BIP-361, if these coins are not migrated to quantum-resistant addresses by the end of the 2031 deadline, they would be effectively burned or frozen in perpetuity.
Critics of the proposal argue that freezing addresses violates the fundamental tenet of “code is law” and Bitcoin’s promise of absolute immutability. “If we can freeze Satoshi’s coins to save the network, we can freeze anyone’s coins for any reason,” argued one prominent developer during an April 23 developer call. Proponents, however, contend that the threat of a quantum actor “sweeping” legacy addresses would cause a catastrophic market collapse, making a proactive freeze the only way to preserve the value of the remaining 19 million coins.
BIP-360 and the Rise of P2MR
Complementing the quantum migration is BIP-360, which introduces a new output type known as Pay-to-Merkle-Root (P2MR). This upgrade is designed to enhance the privacy of the Bitcoin network by hiding public keys from standard transactions until the moment they are spent. In the current environment, public keys are often exposed before a spend, making them vulnerable to pre-computational quantum attacks.
P2MR utilizes Merkle trees to commit to spending conditions, ensuring that only the necessary cryptographic proof is revealed during a transaction. This not only reduces the data footprint on the blockchain—helping to keep node synchronization fast even as the hashrate exceeds 1 ZH/s—but also provides a secondary layer of defense during the long migration to full quantum resistance. Market data from April 2026 shows that nearly 12% of new transactions are already utilizing early implementations of P2MR on sidechains like Liquid, signaling a strong appetite for these privacy-centric upgrades.
Network Health and Mining Dynamics
Despite the intense governance debates, the physical health of the network remains robust. With Bitcoin prices fluctuating between $75,000 and $79,000 throughout April, mining remains highly profitable for those with access to next-generation ASIC hardware. The “structural hand-off” of Bitcoin supply is also accelerating; long-term holders now control approximately 75% of the total circulating supply, or roughly 14.8 million BTC.
This supply crunch is creating a unique environment where technical upgrades like BIP-361 are being viewed through the lens of institutional risk management. Large-scale custodians, now holding over 1.3 million BTC via various exchange-traded products, are reportedly among the strongest advocates for quantum resistance, as they seek to guarantee the multi-decadal safety of their underlying assets. As we move into the second half of 2026, the resolution of the BIP-361 debate will likely define the next era of Bitcoin’s history.
The cryptocurrency market remains highly volatile. This article is for informational purposes only and does not constitute financial advice.
Related: Bitcoin Eyes $80,000 Milestone as Institutional Dominance Hits 60% Amid CLARITY Act Momentum | Bitcoin Institutional Maturity Phase: Network Hash Rate and ETF Absorption
Also read: Algorand Surges 6% as Google and Coinbase Endorse Post-Quantum Leadership
bip-361 freezing legacy addresses that dont migrate is the most controversial thing in bitcoin since the block size wars. immutability vs security
freezing addresses feels like a slippery slope even if the quantum threat is real. who decides the timeline?
Chen the timeline is proposed by devs but ultimately enforced by economic majority. if exchanges and miners dont upgrade the freeze is toothless
core_dev_lurker economic majority decides but exchanges control the economic majority. if Binance and Coinbase say upgrade everyone else follows
Henrik Larsson exactly. coinbase and binance effectively decide bitcoin governance. if they upgrade the freeze the rest follow
freezing dormant wallets as a security measure is the most ironic proposal in bitcoin history. the whole point was nobody can freeze your coins. now the devs want to do it themselves
satoshi_ghost_ the irony is painful. built a network specifically so nobody could freeze your coins and now devs are proposing to freeze coins themselves. the quantum threat is real but the precedent is worse
Minjae H. the irony of building an immutable network and then voting to freeze coins is lost on too many people. once that power exists it WILL be used again for non-quantum reasons
the freeze provision is what makes this different from past upgrades. segwit and taproot added capabilities, this one removes them for non-migrators
1 zh/s hashrate and were still debating whether to freeze old addresses. the philosophical battle in btc never ends
Marat 1 ZH/s and the community is still arguing about quantum threats. the hashpower is wasted if the signature scheme is broken. bip-361 is imperfect but necessary
Zara 1 ZH/s of hashrate is meaningless if the signature scheme is broken. the compute power protects against 51% attacks not quantum key extraction
1 ZH/s hashrate and the real threat is signature schemes not 51% attacks. quantum doesn’t care about your mining power
freezing dormant wallets sounds practical until you realize some of those wallets belong to dead people or lost keys. you are punishing victims
BIP-361 freezing dormant wallets after a deadline is the most controversial governance proposal since the block size wars. you are essentially voting to confiscate coins from holders who cant migrate in time
the freeze provision sets a precedent that will never be undone. first its dormant wallets for quantum safety, then its sanctioned addresses, then its whatever the economic majority decides
quantum_dread_ the freeze provision sets precedent that will never be undone. first dormant wallets then sanctioned addresses then whatever the economic majority wants
Joon B. first dormant wallets for quantum safety then sanctioned addresses then whatever the economic majority decides. the slope isnt slippery its a cliff
freeze_slippery_ the escalation path is obvious. dormant wallets today, sanctioned addresses tomorrow, politically inconvenient ones next year. every precedent in Bitcoin governance eventually gets stretched
The quantum threat timeline feels accelerated. This “freezing” proposal sets a dangerous precedent for governance over user funds.
Forced migration is not the answer. Why should long-term holders be penalized for not keeping up with technical changes?
Reply to Alex: The timeline IS accelerated. We need post-quantum signatures NOW, but this “freeze” approach is too authoritarian.
1 ZH/s hashrate milestone while debating whether to break immutability. we built the most powerful computer network on earth to protect money that devs now want to freeze. make it make sense
1 ZH/s hashrate milestone while simultaneously debating whether to freeze legacy wallets. we built the most secure network on earth just to argue about confiscating coins from people who lost their keys
1 ZH/s of hashrate means nothing against a quantum adversary extracting private keys from public signatures. the freeze is ugly but doing nothing is worse
quantum_pragmatist_ 1 ZH/s hashrate is impressive against traditional attackers but quantum extraction doesnt compete with mining. it targets exposed public keys in the UTXO set directly. apples and oranges
1 ZH per second hashrate while debating whether to confiscate legacy coins. bitcoin built the most powerful computing network on earth just to argue about freezing wallets