Metropolis is finally (almost) here! The fork for Byzantium, the first and larger part of Metropolis, succeeded on the testnet over two weeks ago, and the likely date for the fork on the mainnet has been set to block 4.37 million, which is expected to be on Oct 17. New features include opcodes such as REVERT and RETURNDATACOPY, as well as precompiles that can be used to support a wide array of cryptographic algorithms. At the same time, we have been seeing many improvements to Ethereum core code, Whisper, Swarm as well as Ethereum’s future scaling plans.

The research team has added one full-time new developer and one part-time to Viper, and there is an increasing number of community contributors. Features being worked on include:


We are making progress with syncing to the test and main networks. Now cpp-ethereum can import warp snapshot and continue syncing from the snapshot block.The Byzantium implementation has been finished. Since the last roundup:


Since the last roundup, Geth saw a major release (v1.7.0) and a follow up maintenance release (v1.7.1) with primary focus being on the upcoming Byzantium hard fork (enabled for all networks as of v1.7.1).

In addition to Byzantium, a few features finalized (some of which you may have seen in the v1.7.0 Megara blogpost):

Some important features we’re currently working on (but might take a bit of time due to Devcon preparations) includes:


A plethora of bugfixes have also been merged into both releases, which you can skim through at the GitHub milestones for v1.7.0 and v1.7.1.



Test cases for Byzantium are ready and some clients passed all of them. After the last round up, we:


Yellow Paper


All Byzantium changes have been documented on pull-requests. The next issue to address is the treatment of the empty account states on precompiled contracts, where different clients do different things. A GitHub issue was created to discuss this.

Formal Verification

@pirapira gave talks at the ARM Research Summit and at TU Berlin. We Implemented RLP in OCaml, available with opam install rlp.


We started writing a specification. External interfaces are being implemented.

EVM 1.5

Solidity assembly can now handle EIP #615 opcodes for subroutines and the rest, thanks to Alex.  Initial implementations of both EIP #615 and EIP #616 are written, and reviewed by Andrei, and testing has begun.  Greg is working to present initial performance measurements at Devcon.


web3.js 1.0 beta received a great deal of community contributions which is exciting as it appears 1.0 is already being used a lot in the wild. Please be careful using the account generation and signing, as it has not been audited. Those accounts should not hold any significant amount of ether. We are currently at beta.22. If everything goes well, we hope to have a 1.0.0 Release candidate by Devcon3. recently added features and improvements including:


Development continues to progress, moving us closer to an early alpha release, which will allow running py-evm as a light client.

Ethereum Tester

Ethereum Tester is a new tool for python developers design to provide a standard API for testing applications that interacts with the EVM. The library uses a pluggable backend system that allows swapping out the underlying VM implementation. This library can also be used transparently with by using the experimental EthereumTesterProvider


Two very important PRs has been pushed recently: (1) a terminal that allows tracking transactions and interacting with web3, and (2) a revamp of the UI.

We are now fixing bugs and helping the community to adjust to this new GUI.

A number of new features are being worked on for release in the coming weeks:

- Highlight of declarations and references, basic autocomplete and renaming



We are close to finishing the new ABI en/decoder using the iulia language. This allows passing structs and arbitrarily nested arrays across function calls. It is also a little stricter when it comes to invalid input data including invalid array lengths. You can use pragma experimental ABIEncoderV2; to activate it. With a similar statement, pragma experimental “v0.5.0”; you can activate upcoming breaking changes, which we are adding one after the other. You can now use </span><a href=""><span style="font-weight: 400;">f.selector</span></a><span style="font-weight: 400;"> to access the selector (also called the “function hash”) of a function. Using the default visibility of a function will generate a warning now, and should make you aware of unintended public functions. Finally, Solidity is warning about (and more strictly enforcing if you opt to already activate v0.5.0 features) violations of “view” (formerly called “constant”) and “pure” annotations for functions. After Byzantium, a call to a “view” function will use the new STATICCALL opcode and thus enforce the “view” aspect of the function at VM level.


Released version 0.9.1:



A cross-language differential fuzzer of operations on the alt_bn128 elliptic curve, which are required to perform zkSNARK verifications, in three different clients (Parity, Geth and CPP), in order to find discrepancies between these implementations, has been built. Driven by the libFuzzer engine, the program autonomously creates inputs that lead to new code paths in any of the implementations. In addition to that, it validates that the output of each implementation for any input is the same.

Based on this work, a fuzzer that tests the Parity and Geth implementations of the EVM for equivalence is being developed.

We have been continuing cross-EVM fuzzing efforts in order to find discrepancies between EVM-implementations (Geth, CPP and Parity), and have doubled the bounty rewards for bugs related to consensus or denial-of-service (geth).

The hive-testing framework has been updated to test four clients (geth, cpp, py, parity) with the new Byzantium tests.

An external audit of Mist is in the final stages, and an RCE-vulnerability has been patched and released (credits to Yoonho Kim via the bug bounty program). We strongly recommend updating to the most recent version of Mist!


Since the last roundup, several new contributors have stepped in to assist with development.  EthereumJS is now passing most Byzantium state and blockchain tests. The development effort continues with general bug fixes and code refactoring. The most notable of these efforts is a refactor of the library to add support for JavaScript big integers.


The swarm team merged important new updates and additions into master including the network testing and simulations framework for p2p with a 3D visualiser, improved scheduling for breaking up and reassembling data – the pyramid chunker with the new Binary Merkle Tree  chunk hash, which brings  compact inclusion proofs verifiable on the blockchain, and improved more informative error messages. The network layer rewrite (our major features for POC3) has completed the first phase and pss v1.0 is dev ready now with diffie hellman key-exchange and continually updated keystream.

Our team is engaging in ever more community cooperation to develop certain features on our roadmap by allowing external contributors to feel part of the wider team. We are launching 5 working groups about 5 of our most relevant subprojects: network simulation, pss node to node messaging, media and data streaming, database services and the swap swear and swindle framework for incentivizing bandwidth sharing and long-term storage of data. The latter is now gaining momentum as the third orange paper is being worked on with the draft version first to be presented on 11th October in the London Ethereum Meetup.

We just published the tentative program for Devcon3 breakout session on p2p technology and the blockchain (10:30am-4:30pm, 4th November, 2017).


Thanks to all the developers and team leads who contributed to the sections on their projects!