What is Bitcoin Unlimited?

Bitcoin Unlimited was a proposed upgrade for Bitcoin block size limits which was a hard fork from Bitcoin Core. With Bitcoin’s block sizes limited to 1MB, some community developers were concerned about how the network would cope as more users were adopting it and the number of transactions increased.

Bitcoin Unlimited’s solution would have been to allow miners to set their own block limits, with the largest chain becoming the one adopted. However Bitcoin Core rejects any blocks that are over 1MB in size, which would have led to a hard fork from the original Bitcoin chain. This led to the proposal failing for Bitcoin’s original chain as there were concerns that this would lead to divisions in the Bitcoin community.

Following on from Bitcoin XT and Bitcoin Classic, Bitcoin Unlimited can be used to validate blocks for Bitcoin Cash – a Bitcoin hard fork – which allows for block sizes up to 32MB.

Supporters argue that Unlimited gives greater flexibility to miners, whereas critics argue that upgrades such as SegWitt have helped to improve Bitcoin’s original chain’s scalability.