Bitcoin forks list 2017
At least three of these incidents resulted in an identifiable chainsplit, lasting approximately 51, 24, and six blocks, inandrespectively.
A loosening of the bitcoin forks list 2017 rules on block validity, such that some blocks previously considered as invalid are bitcoin forks list 2017 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 Bitcoin forks list 2017 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 bitcoin forks list 2017 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 bitcoin forks list 2017 identifiable chainsplits. The most recent of these occurred on 4 Julyduring 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. Bitcoin forks list 2017 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. Bitcoin forks list 2017 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 Bitcoin forks list 2017 74, 0.
Softfork A chainsplit occurred. Around five hours after the incident, a fix was released, client 0. This incorrect limit still exists. In Septemberthe 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 enoughso the evaluation point was delayed until 15 March. A successful rollout occurred. This caused a chainsplit on 11 Marchalthough the software which caused the error was released 20 days earlier on 20 February The change was reverted as the Bitcoin economy and miners switched back to 0.
No change in the consensus rules A chainsplit of at least 24 bitcoin forks list 2017 occurred, with the 0. The original rules chain eventually re-took the PoW lead. The rule expired on 15 Maya flag-day hardfork.
Softfork There is no evidence of any issues. Hardfork There is no evidence of any issues. A chainsplit occurred, lasting six blocks, as some miners signaled support for BIP66 but had not upgraded and were SPY mining. The new softfork rules chain eventually took the lead. Therefore, the risk of a chainsplit was elevated in this period. Softfork Flag-day softfork appeared to succeed with no issues, although only a minority of users enforced BIP rules, which have since expired.
The software was upgraded in April to fix this bug, but the new rule does not apply until the 23rd century. Softfork The softfork is not applicable yet. BitMEX Research, GitHub, Bitcoin blockchain Notes With the exception of bitcoin forks list 2017 1MB blocksize limit, prior to the BIP16 softfork, there was no activation methodology, so if the fork occurred smoothly without a chainsplit, there is not necessarily a specific block height or date on which the consensus fork occurred.
There are no consistent definitions used in the above table because, for example, a different definition of the date on which the fork occurred may be more relevant in each incident, depending on the circumstances. Others have mentioned that changes to the P2P protocol can also be considered hardforks if they make previous software releases unusable, since they can no longer connect to the network. Strictly speaking, however, these do not relax the rules on block validity and one could sync old nodes by setting up a relay of intermediary versions of the software.
These changes are excluded from the above list. Using the same logic, the block checkpoint scheme can also be considered as softforks.
In Julythe chain selection rule was altered to shift to most accumulated work from the number of blocks. Technically, this is not a change to block validity rules; however, this change does share some of the risks associated with consensus rule changes. Was the incident a hardfork? When discussing this incident, Bitcoin developer Gregory Maxwell said: A split in the blockchain, resulting in two separate chains, with a common ancestor.
Some users had trouble upgrading and it was recommended that nodes should be shut down if they could not be upgraded. Fixing a critical bug which enabled anyone to spend any Bitcoin.
Output-value-overflow bug fix following a Adding the 20,signature operation limit in an incorrect way. Adding the 1MB blocksize limit. Disallow transactions bitcoin forks list 2017 the same TXID, unless the older one was fully spent. Bitcoin forks list 2017 hash P2SH allows transactions to be sent to a script hash address starting with 3 instead bitcoin forks list 2017 a public-key hash addresses starting with 1.
A chainsplit of at least 24 blocks occurred, with the 0. This was a temporary softfork, bitcoin forks list 2017 a new rule requiring that no more than 4, TXIDs are referenced by inputs in a block. In Augusta block may have been produced that violated the original 10,BDB lock limit rule, which was relaxed on 15 May Check Lock Time Verify enables funds to be locked until a specific time in the future. This temporary softfork makes signaling for the SegWit bitcoin forks list 2017 mandatory for a two week period following 1 August bitcoin forks list 2017 Flag-day softfork bitcoin forks list 2017 to succeed with no issues, although only a minority of users enforced BIP rules, which have since expired.
Fixed a 21 million coin bitcoin forks list 2017 cap bug.