The Ethereum network will be undergoing a hard fork at block number 2,675,000, which will likely occur between 15:00 and 16:00 UTC on Tuesday, November 22, 2016. A countdown timer can be seen at https://fork.codetract.io/. The Morden test network will be undergoing a hard fork at block number 1,885,000.

As a user, what do I need to do?

Download the latest version of your Ethereum client:

What happens if I do not update my client?

If you are using an Ethereum client that is not updated for the upcoming hard fork, your client will sync to the pre-fork blockchain once the fork occurs. You will be stuck on an incompatible chain following the old rules and you will be unable to send ether or operate on the post-fork Ethereum network.

Importantly, if your client is not updated, it also means that any transactions you make will still be susceptible to replay attacks.

What if I am using a web or mobile Ethereum wallet like MyEtherWallet or Jaxx?

Ethereum websites and mobile applications that allow you to store ether and/or make transactions are running their own Ethereum client infrastructure to facilitate their services. Generally, you do not need to do anything if you use a third party web based or mobile Ethereum wallet. However, you should still check with your web or mobile Ethereum wallet provider to see what actions they are taking to update for the hard fork and if they are asking their users to take other steps.

In particular, you should ensure that transactions are generated with the new replay-protected EIP 155 scheme.

What do I do if my Ethereum client is having trouble syncing to the blockchain?

Make sure you have downloaded the latest version of your Ethereum client.

Why are we proposing to hard fork the network?

“Spurious Dragon” is the second hard fork of the two-round hard fork response to the DoS attacks on the Ethereum network in September and October. The previous hard fork (a.k.a “Tangerine Whistle”) addressed immediate network health issues due to the attacks. The upcoming hard fork addresses important but less pressing matters such as further tuning opcode pricing to prevent future attacks on the network, enabling “debloat” of the blockchain state, and adding replay attack protection.

What changes are a part of this hard fork?

The following Ethereum Improvement Proposals (EIPs) describe the protocol changes implemented in this hard fork.


DISCLAIMER This is an emergent and evolving highly technical space. If you choose to implement the recommendations in this post and continue to participate, you should make sure you understand how it impacts you. You should understand that there are risks involved including but not limited to risks like unexpected bugs. By choosing to implement these recommendations, you alone assume the risks of the consequences.