ECIP 1072: Yingchun EVM and Protocol Upgrades Source

AuthorWei Tang

Simple Summary

Enable the outstanding Ethereum Foundation Istanbul network protocol upgrades on the Ethereum Classic network in a hard-fork code-named Yingchun to enable maximum compatibility across these networks.

In particular, delay EIP-1884 activation until backward compatibility solutions are in place on Ethereum Classic.


Add support for a subset of protocol-impacting changes introduced in the Ethereum Foundation (ETH) network via the Istanbul hardforks.

This document proposes the following blocks at which to implement these changes in the Classic networks:

  • TBD on Mordor Classic PoW-testnet (Feb 5th, 2020)
  • TBD on Kotti Classic PoA-testnet (Feb 12th, 2020)
  • TBD on Ethereum Classic PoW-mainnet (March 25th, 2020)

For more information on the opcodes and their respective EIPs and implementations, please see the Specification section of this document.


To enhance the Ethereum Virtual Machine’s (EVM) capabilities, various opcodes shall be added to the Ethereum Classic networks, all of which have been in use on the Ethereum Foundation networks since end of 2019.

This enables all EIPs in Istanbul, but EIP-1884, due to backward compatibility considerations.


Enable the following EIPs at the hard fork block:

  • EIP-152: Add Blake2 compression function F precompile
  • EIP-1108: Reduce alt_bn128 precompile gas costs
  • EIP-1344: Add ChainID opcode
  • EIP-2028: Calldata gas cost reduction
  • EIP-2200: Rebalance net-metered SSTORE gas cost with consideration of SLOAD gas cost change


Adoption of the content of this ECIP requires a hard fork as it introduces changes that are not backward compatible.

The following clients with Ethereum Classic support implement the Istanbul features currently:

  • Parity Ethereum
  • Multi-Geth
  • Hyperledger Besu

This work is licensed under Apache License, Version 2.0.