In this article we cover two main issues, which are the two most frequently raised concerns of those who are interested in the mission we are pursuing - freeing bitcoin from the current block size limit.

1. How bitcoin8m is created?

Bitcoin8m core is simply a modified version of bitcoin core to start accepting block of weight up to 8 times the regular MAX_BLOCK_WEIGHT (which is defined at 4000000) if 1000 consecutive blocks in the past show acceptance of big blocks. For every release of bitcoin core, we release a similar version with a different versioning convention that contains just the above tweak. For example, if version 0.21.0 is released for bitcoin core, we will release bitcoin8m core 8.21.0 which is identical with the exception of the above tweak. Bitcoin8m source code can be downloaded from You can just replace the bitcoin core binary with bitcoin8m binary of compatible version and everything should continue to work as usual.

2. Will it cause a hard fork?

Bitcoin8m core is programmed based on version bits-based signalling technique to only start accepting large blocks only if big block support is signaled in 950 of the most recent 1000 consecutive blocks. So if a miner decides to mine the large block before the condition is reached, the block will be deemed invalid by both bitcoin8m nodes and bitcoin nodes, so no other miners will work on extending the chain containing the large block. The rest of the network will continue to work on the chain that does not include any large blocks. This should in effect prevent the network from hardfork.

3. What will happen to businesses that transact bitcoin?

Every non-mining node will need to switch to bitcoin8m or compatible binary so it will continue to accept blocks in case large blocks start to be produced. In case a business fails to switch to bitcoin8m node before the first large block appears, it will not see confirmed transactions on its end, and thus the business will experience a temporary disruption. The simple fix is to replace bitcoin core binary with the equivalent bitcoin8m binary and restart the service.