The Byzantium fork (EIP-609) reduces the mining rewards, delays the difficulty bomb, enables contracts to make non-state-changing calls to other contracts, and adds cryptographic primitives for layer 2 scaling.

Changes

• EIP-100: Change difficulty adjustment to target mean block time including uncles

• EIP-140: REVERT instruction in the Ethereum Virtual Machine

• EIP-196: Precompiled contracts for addition and scalar multiplication on the elliptic curve alt_bn128

• EIP-197: Precompiled contracts for optimal ate pairing check on the elliptic curve alt_bn128

• EIP-198: Precompiled contract for bigint modular exponentiation

• EIP-211: New opcodes: RETURNDATASIZE and RETURNDATACOPY

• EIP-214: New opcode STATICCALL

• EIP-649: Difficulty Bomb Delay and Block Reward Reduction

• EIP-658: Embedding transaction status code in receipts

Upgrade Schedule

Releases

• Harmony 2.1.0

• Geth 1.7.2

• Parity 1.7.6