Bitcoin fork planned for September 2026 to implement BLAKE2b

A potential fork of the Bitcoin blockchain is scheduled for September 1, 2026, involving a fundamental change to the hashing algorithm. The proposed split would replace the current SHA-256d algorithm with BLAKE2b.

This change is significant because it operates at a deeper level than typical forks, rendering all existing Bitcoin mining hardware incompatible with the new chain. The viability of the new chain depends on whether miners adopt the new hardware required for the BLAKE2b algorithm.

The project is supported by proponents of Bitcoin Knots, a software variant that implements stricter rules than Bitcoin Core, such as restrictions on storing arbitrary data in blocks. The initiative is led by developer Luke Dashjr, who serves as the chief technology officer at Ocean Mining. Following a test on August 30, 2026, the new chain could be finalized via version 29.4.1 of the Knots software.