What is a Bitcoin SegWit2x?

Bitcoin SegWit2x, also known as SegWit2x or B2X, was a proposed protocol upgrade for the Bitcoin blockchain that aimed to increase the block size limit to 2 megabytes (MB) and activate Segregated Witness (SegWit), a separate upgrade that was implemented in August 2017.

The SegWit2x proposal was first introduced in May 2017 as a compromise solution to the long-standing debate within the Bitcoin community over how to scale the Bitcoin network to accommodate increasing transaction volume and reduce fees. The proposal gained support from a significant portion of the Bitcoin mining community, as well as some exchanges and businesses.

The key components of the SegWit2x proposal included:

1. **Segregated Witness (SegWit):** SegWit is a protocol upgrade that separates transaction signatures (witness data) from transaction data, allowing for more efficient use of block space and increasing the capacity of the Bitcoin blockchain. SegWit was activated on the Bitcoin network in August 2017 through a soft fork.

2. **2MB Block Size Increase:** The SegWit2x proposal included a hard fork to increase the block size limit from 1MB to 2MB, doubling the capacity of the Bitcoin blockchain to process transactions. This was intended to address concerns about network congestion and high transaction fees.

The SegWit2x upgrade was scheduled to occur in two phases:

1. **SegWit Activation:** The first phase involved activating SegWit through a soft fork, which was successfully implemented in August 2017.

2. **2MB Block Size Increase:** The second phase was the hard fork to increase the block size limit to 2MB, which was planned to occur approximately three months after SegWit activation.

However, despite initial support from a significant portion of the Bitcoin community, the SegWit2x proposal faced controversy and opposition from some segments of the community, including developers, users, and businesses. Critics raised concerns about the rushed timeline, lack of consensus, and potential risks associated with a contentious hard fork.

Ultimately, the SegWit2x hard fork was canceled in November 2017, just days before its scheduled activation, due to a lack of consensus among stakeholders and concerns about the potential for a chain split and disruption to the Bitcoin network. As a result, the 2MB block size increase proposed by SegWit2x was never implemented, and Bitcoin continued with its 1MB block size limit.