Ever wondered what happens when Bitcoin software versions stop agreeing? Bitcoin isn’t run by one app. It’s a set of consensus rules enforced by nodes. When versions disagree on what’s valid, a block one node accepts can be rejected by another. If miners and nodes split into two rule sets, the network can partition and form two chains. That’s a fork: sometimes a compatible soft fork, sometimes an incompatible hard fork. Users, wallets, exchanges, and miners then decide which chain has economic value—often the one with more adoption, not just hashpower. Risks: replay attacks, confused balances, exchange losses, and double-spend exposure across chains. So upgrades need coordination, clear activation rules, replay protection, and time for infrastructure to update. Bitcoin doesn’t “auto-merge” disagreement. Consensus is social and technical—and the market ultimately votes.