Changing consensus, VTXOs, nVersion nonce space - Bitcoin Optech Newsletter #395

Bitcoin Optech newsletter #395 is here:

- describes a standard for verifying VTXOs across different Ark implementations
- links to a draft BIP for expanding the miner-usable nonce space in the block header’s nVersion field
- points to extensions to standard tooling for TEMPLATEHASH-CSFS-IK support
- summarizes updates to the Hourglass V2 proposal
- examines perspectives on cryptographic algorithm agility for Bitcoin
- Optech Newsletter #395 Podcast

Jgmcalpine posted to Delving Bitcoin about his proposal for V-PACK, a stateless VTXO verification standard, which aims to provide a mechanism to independently verify and visualize VTXOs in the Ark ecosystem...
https://bitcoinops.org/en/newsletters/2026/03/06/#a-standard-for-stateless-vtxo-verification

Matt Corallo posted to the Bitcoin-Dev mailing list a draft BIP to increase the number of bits available in nVersion’s nonce space for miners from 16 to 24...
https://bitcoinops.org/en/newsletters/2026/03/06/#draft-bip-for-expanded-nversion-nonce-space-for-miners

Antoine Poinsot wrote on the Bitcoin-Dev mailing list about his preliminary work to integrate the taproot-native OP_TEMPLATEHASH soft fork proposal into miniscript and PSBTs...
https://bitcoinops.org/en/newsletters/2026/03/06/#extensions-to-standard-tooling-for-templatehash-csfs-ik-support

Mike Casey posted an update to the Bitcoin-Dev mailing list for the Hourglass protocol to mitigate the market impact of quantum attacks against certain lost coins...
https://bitcoinops.org/en/newsletters/2026/03/06/#hourglass-v2-update

Ethan Heilman wrote on the Bitcoin-Dev mailing list regarding the potential need for RFC7696 Cryptographic Algorithm Agility in Bitcoin...
https://bitcoinops.org/en/newsletters/2026/03/06/#algorithm-agility-for-bitcoin

Pieter Wuille wrote to the Bitcoin-Dev mailing list about the limitations of the cryptographic agility...
https://bitcoinops.org/en/newsletters/2026/03/06/#the-limitations-of-cryptographic-agility-in-bitcoin

Bitcoin Optech will host an audio recap discussion of this newsletter streaming live on X/Twitter Tuesday at 17:30 UTC.