We believe that the best next step for bitcoin would be to activate OP_CHECKTEMPLATEVERIFY (CTV, BIP-119) and OP_CHECKSIGFROMSTACK (CSFS, BIP-348). These opcodes enable functionality for a broad set of uses that will allow bitcoin to preserve and expand its role as a scarce, censorship-resistant store of value.

While there are a few promising proposals to improve bitcoin at the consensus layer which may someday be deployed, we believe that CTV and CSFS are uniquely well reviewed, simple, and have been proven to be both safe and widely demanded.

CTV was first formalized in BIP-119 over 5 years ago. Despite many attempts at refinement or replacement, it has remained the most widely preferred method for enforcing pregenerated transaction sequences using consensus. It unlocks valuable functionality for scaling solutions, vaults, congestion control, non-custodial mining, discreet log contracts, and more.

CSFS is a primitive opcode that has been deployed to Blockstream’s Elements for at least 8 years. It represents no significant computational burden over bitcoin’s most often used opcode, OP_CHECKSIG. It can be combined with CTV to implement ln-symmetry, a longstanding improvement to Lightning. It also unlocks a variety of other use cases.

We respectfully ask Bitcoin Core contributors to prioritize the review and integration of CTV (PR #31989 or similar) and CSFS (PR #32247 or similar) within the next six months. We believe this timeline allows for rigorous final review and activation planning.

This request isn't meant to suggest that these contributors dictate the consensus process, but rather it is an acknowledgement that before these opcodes can be activated, they must be implemented in the most widely used bitcoin client.

As application and protocol developers, we are convinced of the significant benefits that these changes would bring to end users of bitcoin – even if only considering their use for layer 1 security and layer 2 scaling solutions. We are optimistic that given the limited size and scope of these changes in both concept and implementation, they represent a realistic next step in the continuing and important work of preserving bitcoin's unique promise.