Start 9 CEO Matt Hill: BIP 110's Mandatory Signaling Window Could Split Bitcoin This Week
Start 9 CEO Matt Hill joined Simply Bitcoin to break down BIP 110, the Bitcoin soft fork proposal entering its most consequential phase this week, and to explain in plain terms what a chain split would and would not mean for everyday holders.
WHAT HAPPENS AT BLOCK 961,632
From block 961,632 through block 963,647 enforcing nodes reject any block that does not signal bit 4, with lock-in happening no later than block 963,648. That mandatory signaling window, estimated to land around August 7, 2026, will test whether Ocean pool and node runners can force compliance without miner majority support. Hill explained that miners must set a version bit in every block they mine during that window. Any block that fails to set it will be rejected as invalid by nodes running Bitcoin Knots, the client that enforces BIP 110.
BIP 110 needs 55 percent of blocks in one difficulty period to signal the bit, and as of one recent count only a small fraction of blocks mined in the current period had done so. Hill said that gap is exactly why the mandatory window matters: without natural majority support, a chain split becomes a live possibility rather than a theoretical one.
WHY HILL DOES NOT EXPECT A LASTING SPLIT
Hill drew a distinction between soft forks, which restrict what was previously allowed, and hard forks, which loosen the rules. He noted that no soft fork in Bitcoin's history has produced a persistent chain split, while hard forks almost always have, pointing to Bitcoin Cash as the clearest example. On that basis, Hill said he expects any split triggered by BIP 110 to be short-lived rather than permanent, since a single large miner choosing to signal would likely trigger a snowball effect that pulls the rest of the network back into consensus.
THE REAL FIGHT IS OVER HOW BITCOIN CHANGES
Hill argued the more important story is not the technical mechanics but the precedent. He said Bitcoin was never going to reach a scenario where a supermajority of the network agrees on every proposed change, and that convicted minorities pushing forward soft forks, while the rest of the network either counters with a competing soft fork or does nothing, is how the protocol has always evolved. His view is that miners have had the tools to end this peacefully for weeks simply by signaling support and preventing a split entirely, and that their reluctance to do so reflects politics as much as economics.
Hill's practical advice to node operators, regardless of which side of the debate they land on, was to update to the latest version of Start OS before the window opens, since it lets users switch between Bitcoin implementations without needing to resync the blockchain if the situation changes quickly.
This story comes from the Simply Bitcoin Live show. Watch the full episode.
