<p>A new version of the software is implemented, which uses the new rules. The old software will see the new transactions/blocks generated by this new software as invalid after the fork date, while new software will accept it, so the old software and new software will disagree on the longest valid blockchain, creating a hard fork.</p>

CC BY-SA 3.0
2018-04-07T12:06:16.357Z
Thanks for your answer. So, to create new coin, I just need to clone bitcoin repo from github, after change something there, create new software client, which will work only with my chain and start it?
Sizuji
CC BY-SA 3.0
2018-04-07T12:07:43.320Z
Or, I don't need to clone repository, I just need to create new software client with new rules and send a transaction to Bitcoin main chain, blockchain will understand, that this is not correct and create hard fork?
Sizuji
CC BY-SA 3.0
2018-04-07T13:45:14.863Z
@TheWorldNode You also need to 1) choose a different network magic, 2) add replay protection if you want to create a hard fork the proper way.
MCCCS
CC BY-SA 3.0
2018-04-07T16:17:27.713Z
@MCCCS Mmm, ok, replay protection I understood, but what is network magic?
Sizuji
CC BY-SA 3.0
2018-04-07T17:15:20.303Z
Nodes connect to other nodes with the same network magic.
MCCCS
CC BY-SA 3.0
2018-04-07T10:43:14.323Z
2018-04-07T10:43:14.323Z
meshcollider
<p>I understand what is hardfork in theory. Hardfork happens, when the consensus algorithm changes (if I'm wrong, correct me please). Ok, with theory everything is clear, but what about technical side of this question? How exactly hardfork occurs, how exactly chain divides? Thank you for your answers</p>

CC BY-SA 3.0
2018-04-07T18:24:43.483Z
I think this is a confused question. You don't "make" a hardfork. It occurs whenever a group of participants within a cryptocurrency intentionally or unintentionally end up enforcing separate rules, resulting in two currencies.
Pieter Wuille
<blockchain-fork>
How to make hardfork?
Sizuji
# How to make hardfork?

(Asked by: username_0 on 2018-04-07)

I understand what is hardfork in theory. Hardfork happens, when the consensus algorithm changes (if I'm wrong, correct me please). Ok, with theory everything is clear, but what about technical side of this question? How exactly hardfork occurs, how exactly chain divides? Thank you for your answers

**Tags:** blockchain-fork

> **Comments:**
> **username_1**: I think this is a confused question. You don't "make" a hardfork. It occurs whenever a group of participants within a cryptocurrency intentionally or unintentionally end up enforcing separate rules, resulting in two currencies.  

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## 1 answers

### Answer by username_2 on 2018-04-07. Score: 0 | Accepted answer

A new version of the software is implemented, which uses the new rules. The old software will see the new transactions/blocks generated by this new software as invalid after the fork date, while new software will accept it, so the old software and new software will disagree on the longest valid blockchain, creating a hard fork.

> **Comments:**
> **username_0**: Thanks for your answer. So, to create new coin, I just need to clone bitcoin repo from github, after change something there, create new software client, which will work only with my chain and start it?  
> **username_0**: Or, I don't need to clone repository, I just need to create new software client with new rules and send a transaction to Bitcoin main chain, blockchain will understand, that this is not correct and create hard fork?  
> **username_3**: @TheWorldNode You also need to 1) choose a different network magic, 2) add replay protection if you want to create a hard fork the proper way.  
> **username_0**: @username_3 Mmm, ok, replay protection I understood, but what is network magic?  
> **username_3**: Nodes connect to other nodes with the same network magic.  

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