Gavin Andresen Introduces BIP 101 for Larger Block Sizes
Gavin Andresen publishes BIP 101, proposing an increase of the maximum Bitcoin block size to 8 MB with scheduled future increases, intensifying the scaling debate.
On June 22, 2015, Bitcoin Core’s former lead developer Gavin Andresen introduced Bitcoin Improvement Proposal 101 (BIP 101), a controversial plan to expand the maximum block size from 1 MB to 8 MB. The proposal included an automatic doubling of the block size limit every two years until it reached 8 GB, designed to accommodate anticipated growth in Bitcoin’s transaction demand.
Andresen’s proposal was incorporated into Bitcoin XT, an alternative client that became a flashpoint in the broader block size wars. BIP 101 was motivated by concerns that Bitcoin’s limited capacity was leading to congestion, higher fees, and reduced usability for everyday payments. Supporters saw the plan as a necessary step toward mainstream adoption, enabling Bitcoin to scale to handle global commerce.
However, critics argued that such aggressive increases would centralize the network by making it harder for individuals to run full nodes, potentially undermining Bitcoin’s decentralized character. The publication of BIP 101 and its promotion through Bitcoin XT marked a turning point in the scaling debate, exposing deep philosophical divides within the community over how best to scale Bitcoin while preserving its security and decentralization.
While ultimately rejected by the Bitcoin Core development team, BIP 101 played a pivotal role in shaping the contentious discussions that led to SegWit, Bitcoin Cash, and other major scaling solutions.