The developers have come to a consensus on a new date for the hardfork. A group of experts has prepared a new version of Geth and Parity clients for implementation.

The hardfork will be activated when block 2675000 is mined. According to the countdown, the block will be produced in 4 days 8 hours, that is, by 22 November. The new attempt to have a hardfork is called Spurious Dragon. The previous had been scheduled for October 31 but did not take place.

The new version 1.5.0 has taken more than 8 months to be created and received the code name “Let there be light.” It contains solutions to address the recent Distributed Denial of Service (DDoS) attacks by increasing the cost to perform tasks on the Ethereum Virtual Machine (EVM). It will hopefully clear the Ethereum blockchain of spam contracts and erase empty accounts that the attackers used to bloat the network.

All node operators will have to upgrade to the new versions of Geth or Parity clients.

The 1.5.0 release changes the structure of blockchain database, according to the upgrade page at Github. Users will not be able to revert to the previous 1.4.x releases. “If you do want to revert, you’ll need to keep a backup of the chaindata directory or resync,” the Geth description reads.

On 4 November, Vitalik Buterin proposed to implement the new EIP170 protocol to set limits on contract code size. This decision was due to the fact that “there remains one slight quadratic vulnerability in Ethereum.”  The fault could result in overuse of computing resources when calling or referencing a smart contract.

“The solution is to put a hard cap on the size of an object that can be saved to the blockchain, and do so non-disruptively by setting the cap at a value slightly higher than what is feasible with current gas limits (a pathological worst-case contract can be created with ~23200 bytes using 4.7 million gas, and a normally created contract can go up to ~18 kb).”

The previous Ethereum hardfork was held in October at the block 2463000. It resulted in the decrease of DDoS attempts on the network due to raised cost for performing tasks. However, it did not completely sanitise the system of the attacks.

Elena Platonova