Bitcoin holders risk losing real BTC if they sell coins from BIP-110 fork, says developer

Bitcoin developer Kevin Loaec, who flagged the risk on X this week, said large holders could be targeted first. Doing nothing will be a safer option, he stated, as coins that never move cannot be replayed because there is no signed transaction to copy.

How BIP-110 makes this possible

The reason any of this is happening is a proposal called BIP-110, which would keep pictures, text and other non-payment data out of bitcoin transactions for a year.

Changing bitcoin's rules requires miners to agree, and they register that agreement by marking the blocks they produce. BIP-110 needs 1,109 marked blocks out of a 2,016-block stretch, or 55%. (A block is the batch of transactions miners add to the ledger roughly every ten minutes.)

That route is closed but the proposal has a second one written into it. From block 961,632, expected this weekend, computers running BIP-110 software will reject any block that does not carry the mark, whether miners agreed or not.

Almost every block being mined right now does not carry it. So those computers will start rejecting the chain that nearly all of bitcoin's mining power is building.

If some miners continue building a BIP-110-compatible branch while the rest keep mining bitcoin as usual, two competing versions of the transaction history could emerge. It stalls if nobody keeps extending the minority branch, it stalls.