BIP 148

Definition of BIP 148

BIP 148, also known as Bitcoin Improvement Proposal 148, is a user-activated soft fork (UASF) proposed to improve the scalability of the Bitcoin network. It aims to enforce the signaling of Segregated Witness (SegWit), a solution designed to optimize block space and address transaction malleability. The BIP 148 proposal aimed to push miners to activate SegWit by requiring its signal in blocks for them to be considered valid.


BIP 148 can be pronounced phonetically as follows:B – BravoI – IndiaP – Papa1 – One4 – Four8 – EightSo the entire phonetic pronunciation would be “Bravo India Papa One Four Eight.”

Key Takeaways

  1. BIP 148 is a User-Activated Soft Fork (UASF) proposal aimed at implementing the Segregated Witness (SegWit) scaling solution that helps increase the Bitcoin network’s transaction capacity.
  2. It requires that miners signal their support for SegWit by a specific date, and if they don’t, the UASF will activate, causing non-compliant miners to face the risk of being rejected from the network for not implementing the upgrade.
  3. BIP 148 was intended to encourage faster adoption of SegWit to improve the Bitcoin protocol, but it also raised concerns about potential chain splits, which ultimately led to the development of alternative agreements like the New York Agreement and SegWit2x implementation.

Importance of BIP 148

BIP 148, also known as “User-Activated Soft Fork” (UASF), is an important term in the technology domain as it represents a mechanism proposed to improve the Bitcoin network.

This proposal aimed to address the scalability issues in Bitcoin by activating the existing Segregated Witness (SegWit) upgrade, which was intended to increase the network’s transaction capacity.

BIP 148 was designed to bypass the need for support from mining community, thus empowering the users to activate the upgrade on their own.

By implementing BIP 148, users could effectively force miners to comply with the upgrade, fostering a more democratic and decentralized power balance within the Bitcoin community.

Although subsequently a different approach (BIP 91) was implemented to activate SegWit, BIP 148 remains an important example of user-driven network improvements in the blockchain ecosystem.


BIP 148, or Bitcoin Improvement Proposal 148, was introduced as a potential solution to the long-standing issue of Bitcoin’s scaling. Its primary purpose was to facilitate the activation of Segregated Witness (SegWit), an upgrade to the Bitcoin protocol aimed at increasing transaction throughput and solving the malleability problem.

BIP 148, also known as the User Activated Soft Fork (UASF), was a mechanism that allowed Bitcoin users to force miners to implement and activate SegWit. By rallying the support of Bitcoin nodes, BIP 148 sought to bypass potential resistance from miners that were not keen on adopting the upgrade, thus allowing SegWit to become a protocol standard.

The implementation of BIP 148 was an important milestone for the Bitcoin community as it demonstrated the collective power of users in shaping the future of the technology. The proposal gained significant traction in 2017 and successfully pressured miners to adopt the new rule sets even prior to the August 1st, 2017 deadline outlined in the plan.

This led to the activation of the SegWit protocol, which significantly improved Bitcoin’s transaction handling capabilities, increased its scalability, and allowed for continued innovation in the space. BIP 148 set a precedent for active user participation in protocol improvement and served as a reminder that the decentralized nature of Bitcoin is one of its greatest strengths.

Examples of BIP 148

BIP 148 (Bitcoin Improvement Proposal 148), also known as User-Activated Soft Fork (UASF), is a mechanism to activate the Segregated Witness (SegWit) update without requiring the majority of miners to signal their support for it. Here are three real-world examples where BIP 148 played a significant role in Bitcoin’s development:Litecoin’s Activation of SegWit – In April 2017, Litecoin, a popular cryptocurrency based on the Bitcoin blockchain, successfully activated SegWit using a UASF similar to BIP

This served as a testbed for BIP 148 and demonstrated the feasibility of making updates to the Bitcoin network without requiring miner consensus.The New York Agreement – The New York Agreement, also known as the SegWit2x proposal, was a response to the growing support for BIP

The agreement aimed to activate SegWit in Bitcoin’s network while also proposing an increase in the block size limit. The agreement, signed by various Bitcoin organizations and miners, led to the eventual activation of SegWit in AugustBIP 148, therefore, indirectly contributed to the implementation of SegWit by exerting pressure on the Bitcoin community to reach a compromise.

Bitcoin Cash Hard Fork – In August 2017, Bitcoin Cash emerged from a hard fork in the Bitcoin network, partly as a response to the activation of SegWit by BIPSome members of the Bitcoin community believed that SegWit was not enough to scale the network efficiently and opted to create a new cryptocurrency with larger block sizes. The resulting Bitcoin Cash chain allowed for lower fees and quicker transactions, aiming to address the scalability issues that BIP 148’s UASF addressed with SegWit activation.



1. What is BIP 148?

BIP stands for Bitcoin Improvement Proposal. BIP 148 is a proposal aimed at activating the Segregated Witness (SegWit) consensus rule changes on the Bitcoin network. It was designed to be a User Activated Soft Fork (UASF), meaning that it can be activated by users and node operators without the support of miners.

2. How does BIP 148 work?

BIP 148 starts by implementing a new network rule that all nodes must follow. This rule requires nodes to reject any transaction that does not signal support for SegWit. Once this rule is enforced, miners have to signal their support for SegWit to have their blocks accepted by the network.

3. What is the main purpose of BIP 148?

The main purpose of BIP 148 is to activate the SegWit feature on the Bitcoin network. SegWit aims to solve numerous issues present in the network, such as transaction malleability, and enables better scalability and privacy solutions.

4. How does BIP 148 affect the bitcoin network?

Implementing BIP 148 as a UASF means that a part of the network would enforce SegWit, while the rest would not. This may cause a temporary network split and potential issues like replay attacks. To prevent such issues, it is advised that users, exchanges, and wallets upgrade their software to compatible versions.

5. Did BIP 148 succeed in activating SegWit?

Yes, BIP 148 was successful in activating SegWit on the Bitcoin network. The activation was finally achieved through a combination of BIP 91, BIP 141, and BIP 148. The soft fork came into effect on August 24, 2017.


Related Technology Terms

  • Segregated Witness (SegWit)
  • User Activated Soft Fork (UASF)
  • Bitcoin Protocol Upgrade
  • Block Size Limit
  • Transaction Malleability

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