2013-03-11-chain-fork.html

---
title: "11/12 March 2013 Chain Fork Information"
shorturl: "chainfork"
active: false
banner: ""
date: 2013-03-11
---
        <h2 id="what-happened">What happened</h2>
<p>
A bitcoin miner running version 0.8.0 created a large block (at height 225,430) that is incompatible
with earlier versions of Bitcoin.
</p>
<p>
The result was a block chain fork, with miners, merchants and users running the new version of bitcoin
accepting, and building on, that block, and miners, merchants and users running older versions of bitcoin
rejecting it and creating their own block chain.
</p>
        <h2 id="what-is-being-done">What is being done</h2>
<p>
Large mining pools running version 0.8.0 were asked to switch back to version 0.7, to create a
single block chain compatible with all bitcoin software.
</p>
        <h2 id="questions-and-answers">Questions &amp; Answers</h2>
<h3 id="what-should-i-do">I'm not a miner or a merchant, what should I do?</h3>
<p>
Nothing. Your bitcoin software will switch to the correct chain automatically, no matter
which version you are running.
</p>
<h3 id="are-my-bitcoins-safe">Are my bitcoins safe?</h3>
<p>
Yes.
</p>
        <h2 id="what-will-be-done">What will be done</h2>
<p>
The core developers have investigated what caused the old versions to reject the new
blocks, and have released a 0.8.1 version that avoids creating blocks that are incompatible with
older versions. <a href="https://en.bitcoin.it/wiki/BIP_50">A full post-mortem document has been published</a>.
</p>

<div style="text-align:right">
  <i>This notice last updated: Thu, 16 May 2013 01:37:00 UTC</i>
</div>