Individuals
Your coins, keys, and addresses are unchanged. Upgrade a node if you validate the chain yourself.
Learn moreBitcoin: Peer-to-Peer Electronic Cash System
Bitcoin is an innovative payment network and a new kind of money. A node you can run yourself is what keeps it that way. Anyone can still verify the chain. Large miners split from the data limits most nodes were already running, and that split puts images and other arbitrary files on every operator's disk.
What is Bitcoin?
Bitcoin uses peer-to-peer technology to operate with no central authority or banks. Transactions and the issuing of bitcoins are carried out collectively by the network. Its design is public. Nobody owns or controls Bitcoin, and everyone can take part.
Businesses
Exchanges, wallets, and merchants should follow the BLAKE2b chain they intend to credit and list.
Learn moreDevelopers
After the hardfork, consensus requires BLAKE2b proof of work so the old ASIC fleet cannot keep a split that loads images and other junk onto every node's disk. Miners should use Knots and DATUM.
Learn more · MinersWhy this hardfork exists
Bitcoin is cash over a peer-to-peer network. A full node is how an ordinary user checks the books without asking permission. BIP-110, the Reduced Data Temporary Softfork, tried to keep non-payment junk out of blocks while leaving normal transfers alone. That proposal was a softfork. It is not this hardfork. What follows is a response to BIP-110 being blocked.
Large, institutionally aligned mining firms refused those limits. They kept producing blocks most nodes would not take — a hashpower split against prevailing node policy. Anyone can still audit the result. The harm is that every operator who follows those miners must keep whatever they sold into a block, including pictures and other non-payment files.
On August 8, 2026, nodes enforcing BIP-110 stopped accepting blocks that did not signal. Most SHA256d hashpower kept producing those blocks, so the money-only rules could not move. This release switches proof of work from SHA256d to BLAKE2b so that fleet cannot hold a lean chain hostage. Reduced-data rules start at the same height as the new header — a flag day, not a miner vote — and last until the parent block's median time past reaches 1 September 2027, 00:00 UTC. BLAKE2b stays after that window closes.
- Proof of work
- SHA256d → BLAKE2b
- RDTS window
- Until parent MTP 1 Sep 2027 UTC
- Temporary block cap
- 700,000 weight units
Get a quick overview
Fast peer-to-peer transactions
Send value across the network without a central operator. Monetary use is the point of the system.
Worldwide payments
Bitcoin remains a global settlement network. Coins created before the fork stay spendable after it.
Money, and nothing else
Leave pictures and other non-payment files off the ledger so miners cannot force every operator to store them.