Grassroots support for two Bitcoin Improvement Proposals (BIPs) appears to be emerging as potential candidates for Bitcoin’s next soft fork. The proposals in focus are BIP 119 and BIP 348.
BIPs serve as the formal mechanism for discussing proposed changes to Bitcoin. If a BIP garners enough widespread support, it may be integrated into Bitcoin through a soft fork or an update to Bitcoin Core. Such proposals are often referred to by nickname, with multiple BIPs possibly included in a singular soft fork. BIP 119, known as OP_CHECKTEMPLATEVERIFY (CTV), has been under consideration for several years, while BIP 348, denoted as OP_CHECKSIGFROMSTACK (CSFS), was formalized more recently by contributors Jeremy Rubin and Brandon Black.
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The technical community around Bitcoin typically engages in extensive debates about these proposals. A notable visual representation of this intricate and often convoluted discussion process has been provided by the Taproot Wizards, a development firm recognized for their work on Bitcoin NFTs.
In essence, the soft fork process necessitates a rough assessment of support from various Bitcoin stakeholders—including developers, custodians, investors, and miners. Bitcoin miners serve as the most tangible metric for indicating support, as they can signal approval for changes to the codebase by marking their mined blocks. Typically, Bitcoin Core requires a threshold of 95% of blocks over a specific timeframe to signal acceptance before an upgrade is locked in for activation.
However, establishing what constitutes “widespread support” is not straightforward. Bitcoin consensus is an ever-evolving phenomenon, making it challenging to gauge real-world consensus given the decentralized nature of the network.
In recent months, particularly during February and March, we have observed a noticeable shift as numerous developers publicly expressed their support for both BIPs.
What’s in a Proposal?
In recent weeks, a surge of support from various Western Bitcoin developers for CTV and CSFS has been evident on platforms like Twitter, suggesting a collective move towards endorsing certain modifications to Bitcoin.
Both CTV and CSFS pave the way for innovative methods of scripting in Bitcoin. Bitcoin script is the low-level programming language that facilitates the creation and transaction of Bitcoin. CTV was proposed by former Bitcoin core contributor Jeremy Rubin over five years ago; CSFS, on the other hand, was only formalized in November 2024.
These proposals are set to introduce “covenants” to Bitcoin—mechanisms that restrict the future spending capabilities of a wallet. Covenants are anticipated to significantly enhance the self-custody practices, fee management strategies, and existing technologies like Lightning and Ark.
Moreover, these proposals are regarded as “narrowly defined” by developers, implying a lower likelihood of them being exploited in unexpected ways. The Bitcoin development community approaches any proposed changes with a degree of caution. For instance, although BIP 119 has seen little change over these years, its prior consideration as overly aggressive highlights the cautious nature of Bitcoin developers.
A Long Time Coming
As a reminder, Jeremy Rubin’s previous push for CTV faced substantial criticism from notable figures within the Bitcoin community, including Adam Back and Jimmy Song. This criticism led to significant resistance against the proposal, resulting in Rubin stepping back from active involvement in the Bitcoin space.
Recent advocacy for the OP_CAT opcode, outlined in BIP 347, has reframed the discourse surrounding Bitcoin proposals. By positioning CTV and CSFS as more conservative options, the Overton Window of acceptable proposals has expanded. It is essential to note that many advocates of OP_CAT also express support for both BIPs 119 and 348.
Looking ahead, we can expect further discussions among developers at various technical conferences such as OPNEXT in April, BTC++ in July, and TABConf in October. Once developers achieve a rough consensus, the focus will shift to miners, community, and investors regarding the activation of the soft fork.
However, it is important to recognize that there is no formalized process for implementing a Bitcoin soft fork. This leaves many questions unanswered: Will the potential soft fork encompass only CTV and CSFS? Might OP_CAT also join the discourse? What will the activation process entail, and will Bitcoin miners actively participate in recognizing these changes?
As the landscape of Bitcoin continues to evolve, one thing remains clear: stakeholders should prepare to engage with a plethora of abbreviations and technical terminology.
