Bitcoin fork dates history
At least three of these incidents resulted in an identifiable chainsplit, lasting approximately 51, 24, and six blocks, in , and , respectively. A loosening of the consensus rules on block validity, such that some blocks previously considered as invalid are now considered valid. Existing nodes are required to upgrade to follow the new hardforked chain.
A tightening of the consensus rules on block validity, such that some blocks previously considered as valid are now considered invalid. Existing nodes do not necessarily need to upgrade to follow the new softforked chain.
Relative lock-time enables a transaction output to be banned for a relative amount of time after the transaction. Median time-past removes the incentive for a miner to use a future block timestamp to grab more transaction fees. In our view, on balance, the increase in the BDB lock limit a few months after the 11 March chainsplit was a hardfork.
The rule was relaxed on 15 May in software version 0. A block exceeding this limit may finally have been produced on 16 August so one can define the date of the hardfork to be either 15 May or 16 August Indeed, due to the non-deterministic nature of the lock limit, perhaps it is theoretically possible one could have a local system set up such that the old BDB lock limit has never been breached. When discussing this incident, Bitcoin developer Gregory Maxwell said:. Sort of a mixed bag there, you can actually take a pre BIP node and fully sync the blockchain, I last did this with 0.
It just will not reliably handle reorgs involving large blocks unless you change the BDB config too. There were prior bugs fixed where older versions would get stuck and stop syncing the chain before that too… So I think by a really strong definition of creating a blockchain which violates the rules mandated by prior versions we have never had a hardfork.
In the list of consensus rules changes above, there are three incidents that caused identifiable chainsplits. The most recent of these occurred on 4 July , during the BIP66 softfork upgrade.
Immediately after the activation of BIP66, there was a six-block orphan chain created because a miner produced an invalid block that was not recognised as invalid by some other mining pools, because they were not validating new blocks.
If the miners had been validating blocks, they would have discovered the block was invalid and rejected it. Instead, some miners built on top of the invalid block and a chainsplit occurred. A diagram illustrating these six blocks and the chainfork is displayed below. Graphical illustration of the July chainsplit. After the publication of this piece, an alternative list of consensus versions was published on the Bitcoin Wiki. Whilst many claims made in this piece are cited, we do not guarantee accuracy.
We may have made errors or accidentally omitted consensus rule changes from the list. Skip to content Abstract: This can be caused by either a hardfork, a softfork, or neither. Softfork A tightening of the consensus rules on block validity, such that some blocks previously considered as valid are now considered invalid. Softfork No evidence of any issues during this upgrade.
Fixing a critical bug which enabled anyone to spend any Bitcoin Potentially a non-deterministic hardfork No evidence of any issues during this upgrade 15 Aug 74, 0. Softfork A chainsplit occurred.
Around five hours after the incident, a fix was released, client 0. This incorrect limit still exists. In September , the rule was applied to all blocks, apart from 91, and 91,, which violate the rule.
Softfork This was a flag-day softfork. There is no evidence of any issues. Miners did not upgrade fast enough , so the evaluation point was delayed until 15 March.
A successful rollout occurred. Programming the Open Blockchain 2 ed. O' Reilly media, inc. Retrieved 23 April The Decentralized Alternative to Central Banking. Retrieved 17 January A Basic Beginners Guide - Blockgeeks". Retrieved from " https: Bitcoin clients Computing-related lists Clients computing Cryptocurrencies. Pages using citations with accessdate and no URL. Views Read Edit View history.
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