The May 2026 upgrade is now active on Chipnet at block 279,792! 🎉 This upgrade completes the restoration of Bitcoin Script on Bitcoin Cash (CashVM), making CashVM a simple, ultra-efficient, high-level programming environment for sound money. Left: 2016 opcodes, right: 2026 opcodes 🔥 (source: vm.cash) Over the last decade, Bitcoin Cash has delivered: • 2018: Opcode restoration (OP_CAT, OP_XOR, OP_DIV, OP_MOD, etc.), • 2019: Schnorr signatures with multisig batch verification, • 2020: Density-based signature limits, • 2022: OP_MUL and introspection, • 2023: Cross-covenant commitments (CashTokens), • 2025: Density-based general limits and BigInts, • 2026: Loops, functions, bitwise, and Pay-2-Script. Each upgrade carefully preserved Bitcoin Cash's transaction-level parallelization, enabling global-scale, layer-1 throughput – without compromising Bitcoin Cash's scalability, decentralization, and censorship-resistance. Fully-validating, archival BCH nodes run on consumer hardware and still outperform clusters of high-powered, centralized sequencers required by account-based networks. With this upgrade, CashVM becomes even more powerful, allowing contract developers to efficiently implement post-quantum cryptography, homomorphic encryption, zero-knowledge proof systems, and more – without waiting for network upgrades. Case Study: Quantumroot Quantumroot is a quantum-secure vault contract design offering full 256-bit classical, 128-bit quantum security strength. Possible since May 2025, but made 10-100× more efficient by the 2026 upgrade: Quantumroot sweep transactions are 15% smaller per-UTXO than P2PKH wallets. Upgrade Details The 2026 upgrade includes four Bitcoin Cash Improvement Proposals (CHIPs): Loops CHIP Introduces the well-established, OP_BEGIN/OP_UNTIL loop construction to CashVM, bounded by the density-based limits activated in the 2025 upgrade. Loops eliminate duplication in repeated procedures, significantly reducing transaction sizes and enabling previously impractical constructions. Functions CHIP Enables factoring of contract bytecode into reusable functions with OP_DEFINE/OP_INVOKE, eliminating duplicated logic and reducing transaction sizes. Functions improve the efficiency of complex financial and cryptographic computations, including zero-knowledge proof verification, homomorphic encryption, post-quantum cryptography, and more. Bitwise CHIP Re-enables bitwise operations, including OP_INVERT for bit inversion, arithmetic shifts (OP_LSHIFTNUM and OP_RSHIFTNUM) for numeric values, and binary/logical shifts (OP_LSHIFTBIN and OP_RSHIFTBIN) for binary data. These operations allow CashVM contracts to more efficiently implement a variety of financial and cryptographic algorithms. Pay-2-Script CHIP Makes Pay-2-Script (P2S) outputs standard, enables longer token commitments (up to 128 bytes), and unifies the standard unlocking bytecode length limit with the consensus limit (10,000 bytes). These changes improve wallet ecosystem safety, simplify contract design, and reduce transaction sizes for many vault, multi-party covenant, and decentralized financial applications.Technical Specs For more details, see the CHIPs: - Loops: github.com/bitjson/bch-loops - Functions: github.com/bitjson/bch-funct… - Bitwise: github.com/bitjson/bch-bitwi… - Pay-2-Script: github.com/bitjson/bch-p2s

Since May 2023, Bitcoin Cash contracts have been able to implement: zk-SNARKs, STARKs, BLS signatures, Lamport signatures & hash-based signature schemes, post-quantum cryptography, verifiable delay functions, bulletproofs, ring signatures, confidential transactions (within covenants), homomorphic encryption, multi-party computation, and any other cryptosystem being implemented on or in any other cryptocurrency. (Note these were also possible on Bitcoin Cash in 2009, but they were broken by the 2010 emergency anti-DoS patches.) Bitcoin Cash's May 2023 upgrade allowed computations to be split across inputs and/or transactions, so even without further upgrades, it is already possible to perform any kind of computation within Bitcoin Cash contracts. In practice though, important use cases require KBs or MBs of transactions to incrementally complete a computation, presenting a practical barrier to development and deployment. After the 2025 BCH upgrade, many constructions that would have ballooned transaction sizes by KBs or MBs will now require only a few bytes: larger stack items and bigint arithmetic bring down these transaction sizes by 10-100x. Technically only a quantitative improvement, but significant enough to feel qualitative. So for the record, BCH has been computationally universal since May 2023, the 2025 upgrade just makes things more efficient: smaller transactions, lower fees, and simplified development/security audits. For comparison, I'll note again that these constructions have also been possible on ETH since it's inception (but with higher fees), and BTC since the Taproot Schnorr hack (but with KBs or MBs of waste in transaction sizes vs BCH).

While some computations are still impractical (requiring loop unrolling and/or multi-input computation), I think BCH is within 1-2 years of exceeding ETH in contract efficiency across all remaining classes of computation. VM limits were the messiest problem blocking Bitcoin Cash VM development since 2010. The 2025 BCH upgrade gets past that wall, and most upgrades from here are relatively simple, incremental, and self contained. For 2026, I’m hoping to see (at least) loops, exponentiation, and relaxed output standardness (“Pay-2-Script”). Just those would close most remaining gaps + extend BCH's lead in areas where it already excels. Of course, I'm aiming at "gaps" which don't matter to most use cases. With BCH's architectural advantages, BCH can already offer better DeFi experiences with far less byte-efficient contract code. Contract compute is already >100x cheaper for BCH users than the equivalent transaction fees for ETH users, and BCH fees remain reliably low, even during bursts of 10-100x network load.

This is not part of the 2025 Bitcoin Cash upgrade, but over the next few years I expect to see Bitcoin Cash covenants that allow users to deposit BCH and CashTokens and receive "privacy-wrapped" BCH and CashTokens. Within these privacy covenants, users can indefinitely transact with strong privacy, and transactions/withdrawals will not be possible to link to a previous transaction. With layer 1 transparency, you'll always be able to see the covenant's total BCH and CashToken(s) balances, but individual holdings and transaction info won't be leaked. These systems are possible on any cryptocurrency with sufficiently advanced math capabilities in the contract layer. It's actually been possible (but hard) on BCH for a while, various teams claim to have partial support on BTC, and of course multiple such systems have existed on ETH for years. I think this application-layer privacy approach – full transparency on layer 1 + a good calculator – has better tradeoffs than systems that bet their layer 1 network on monolithic privacy solutions. Full layer 1 transparency increases the addressable market (and ultimately – anonymity set size), eliminates supply auditing concerns, and minimizes existential cryptography risks. With a well designed virtual machine (the "calculator"), transaction sizes and validation costs can be practically equivalent, while only the application-layer privacy approach can fully isolate privacy systems, maximizing user choice to 1) individually opt in, 2) switch and diversify across systems, and 3) deprecate/ignore outdated or vulnerable systems.

The May 2025 upgrade to Bitcoin Cash is now active on chipnet at block 227,228! 🎉 (0000000000b8dc4625844fa367b12317645fac7c9afbc5fb8def4025a6822c86) This upgrade includes two Bitcoin Cash Improvement Proposals (CHIPs): Targeted Virtual Machine Limits CHIP The VM Limits CHIP retargets Bitcoin Cash's Denial-of-Service limits to extend compute for real contracts by more than 100x while reducing worst-case node compute usage by 50%. By reducing overhead, the retargeted limits simplify contracts, reduce transaction sizes, streamline contract audits, and improve overall security. By improving contract efficiency, this upgrade also makes important use cases more practical, including post-quantum cryptography, stronger escrow and settlement strategies, zero-knowledge proofs, homomorphic encryption, and other crucial innovations for the future security and competitiveness of Bitcoin Cash. Finally, this upgrade raises the bar by contributing new tooling and a cross-implementation benchmarking methodology to continuously verify node performance. Beyond empirically verifying the safety and correctness of the upgrade, these tools will simplify development of new production-ready implementations, prevent regressions in existing implementations, and reduce the cost of verifying implementation-specific software updates. BigInt CHIP: High-Precision Arithmetic for Bitcoin Cash The BigInt CHIP enables high-precision math for Bitcoin Cash, offering over 10x reductions in contract lengths and making previously-theoretical use cases immediately practical: more advanced automated market making and exchange protocols, decentralized stablecoins, collateralized loan protocols, cross-chain and sidechain bridges, zero-knowledge proofs, post-quantum cryptography, homomorphic encryption, and more. This upgrade takes full advantage of Bitcoin Cash's fundamentally more scalable architecture to offer math capabilities which exceed those of Ethereum: "bare metal" performance, more byte-efficient transactions, far lower transaction fees, and protocol-level simplicity that eliminates whole classes of Ethereum contract vulnerabilities. These capabilities are available to Bitcoin Cash contracts on "layer one" – ensuring security, censorship resistance, and cross-contract compatibility – without increasing compute requirements: fully-archiving Bitcoin Cash nodes can continue to run on inexpensive, consumer hardware. Learn More To learn more about the upgrade or the CHIP upgrade process, please see this earlier post: xitter.cf/bitjson/status/1856928…

Bitcoin Cash's November 15th chipnet lock-in is almost here, and the VM Limits & BigInt CHIP upgrades are expected to activate in 2025! 🚀 If you run a node on chipnet, please upgrade today! Over the past 6 weeks, we’ve been requesting final approval from all stakeholders: over 400 companies, organizations, and projects from across the Bitcoin Cash (BCH) ecosystem. We recognize that taking a public position on a network upgrade requires time, resources, and commitment to advancing Bitcoin Cash. Thank you to all of the organizations and individuals who have participated during this lock-in process. Thank you to all contributors to these proposals. Technical feedback has been incorporated over dozens of revisions, and the upgrade is now meticulously optimized and widely reviewed – over 6 months before mainnet activation. My summary, endorsement, and links to the VM Limits CHIP: xitter.cf/bitjson/status/1842044… My summary, endorsement, and links to the BigInt CHIP: xitter.cf/bitjson/status/1842045… Again, if you run a chipnet node, be sure to upgrade before chipnet activation: ~30 hours from the time of this post! Verified builds and a docker image are available: xitter.cf/ChaingraphCash/status/…

Congrats to @cashonize on the rebranding! Cashonize is a fantastic web-based #BitcoinCash wallet for #CashTokens by @GeukensMathieu. Cashonize was the first wallet to launch CashTokens support, working on chipnet months before the mainnet upgrade. 🚀 $BCH #Bitcoin