BIP54 updates from the last several months of Consensus Cleanup work
Implementation progress:
Bitcoin Core: github.com/bitcoin/bitcoi… (open) implements BIP54's rules without mainnet activation. Needs reviewers.
libbitcoin: github.com/libbitcoin/lib… (merged)
rbitcoin: github.com/reardencode/rb… (draft, signet)
btcd: github.com/btcsuite/btcd/… (draft)
Research: Pieter Wuille published a proof, machine-checked in Lean, that BIP54's two timestamp rules together bound chain length for a given amount of work. delvingbitcoin.org/t/bounds-on-ch…
64-byte txs: Jeremy Rubin argued they may have legitimate uses (groups.google.com/g/bitcoindev/c…) and wrote up an alternative that invalidates merkle internal nodes instead (groups.google.com/g/bitcoindev/c…). BIP54's rationale now acknowledges that option but still prefers the simple ban.
BIP54 tracker for forward-compatibility for miner coinbase locktimes: mainnet.observer/charts/transac…
Other discussions:
Antoine Riard's response to Mark Friedenbach's objection that fixing timewarp forecloses forward blocks groups.google.com/g/bitcoindev/c…
An idea to split BIP54 into one BIP per fix, which the authors declined github.com/bitcoin/bips/p…
Testnet5 (BIP95): enforces BIP54 from block 1 groups.google.com/g/bitcoindev/c…
bip54.org is updated to reflect these.
Implementation progress:
Bitcoin Core: github.com/bitcoin/bitcoi… (open) implements BIP54's rules without mainnet activation. Needs reviewers.
libbitcoin: github.com/libbitcoin/lib… (merged)
rbitcoin: github.com/reardencode/rb… (draft, signet)
btcd: github.com/btcsuite/btcd/… (draft)
Research: Pieter Wuille published a proof, machine-checked in Lean, that BIP54's two timestamp rules together bound chain length for a given amount of work. delvingbitcoin.org/t/bounds-on-ch…
64-byte txs: Jeremy Rubin argued they may have legitimate uses (groups.google.com/g/bitcoindev/c…) and wrote up an alternative that invalidates merkle internal nodes instead (groups.google.com/g/bitcoindev/c…). BIP54's rationale now acknowledges that option but still prefers the simple ban.
BIP54 tracker for forward-compatibility for miner coinbase locktimes: mainnet.observer/charts/transac…
Other discussions:
Antoine Riard's response to Mark Friedenbach's objection that fixing timewarp forecloses forward blocks groups.google.com/g/bitcoindev/c…
An idea to split BIP54 into one BIP per fix, which the authors declined github.com/bitcoin/bips/p…
Testnet5 (BIP95): enforces BIP54 from block 1 groups.google.com/g/bitcoindev/c…
bip54.org is updated to reflect these.
github.com Implement BIP 54 (Consensus Cleanup) without mainnet activation by darosior · Pull Request #35793 ·... This implements the Consensus Cleanup validation rules proposed in BIP 54. These rules are only enabled on regtest. Mainnet activation, if any, is to be considered separately. This patchset is base... 
