Road to Istanbul: ETH Hard Fork Explained
Istanbul is a large and glorious city located on the verge of Europe and Asia. But not only. Istanbul is the name of the eighth hard fork in the Ethereum’s network. It went live on December 8th at block 9,069,000. Following this year’s St. Petersburg and Constantinople forks, Istanbul represents the network’s version of 1.8. It became another essential step on the way towards ETH 2.0 that will introduce the PoS protocol.
Why Istanbul is important at all? How it changed Ethereum? What’s next? Let’s try to figure it out together with the Superorder team.
Forks in Blockchains
First things first, let’s understand the nature of Istanbul as a hard fork. In open-source development, a fork is a copied version of the initial code that continues developing separately. However, blockchains feature a bit different concept. They rely on the public consensus that is often difficult to reach. Thus, communities may split when users can’t agree on a certain decision or want to make a major upgrade.
There are two types of blockchain forks:
- Soft fork. An upgrade that is backward-compatible with old versions. Soft forks don’t split chains because all nodes can interoperate freely. Generally, they are much safer and easier to develop.
- Hard fork. A large upgrade that isn’t compatible with legacy blocks. Users must reach the majority upgrade or they risk splitting into two active chains.
By purpose, hard forks divide into three groups:
- Network upgrades. Significant updates of the main network that are planned years ahead. Istanbul falls into this category.
- Network contentions. Lack of consensus between developers and/or miners. The DAO fork is the most famous result of such contention.
- Code changes. Launches of new cryptocurrencies. Ethereum didn’t have these forks but Bitcoin implemented such changes by creating Zcash.
As for Ethereum, it featured both types. Soft forks like the first part of Metropolis introduced various system upgrades for blocks backward-compatible with other blocks. Hard forks with a reached consensus like Homestead or this year’s Istanbul came with even more significant changes that aren’t compatible with older versions. Finally, a hard fork without consensus — The DAO — resulted in the launch of Ethereum Classic.
Istanbul Fork Changes
Istanbul introduced one of the last major upgrades before the full switch to ETH 2.0 with PoS. Most likely, it will take one year or so to switch but this hard fork established the required basis.
Overall, there are six key changes that emerged from six accepted Ethereum Improvement Proposals (EIPs):
- EIP-152 — improved Ethereum and Zcash interoperability by introducing features like atomic swaps. Also, it boosts privacy.
- EIP-1108 — decreases the price of precompile gas costs. As a result, it improves scalability and privacy, again.
- EIP-1344 — allows developers accessing and changing chain IDs. The feature is based on the ChainID opcodes.
- EIP-1884 — raises the price of certain opcodes related to the network’s processes. It helps to keep the balance between costs and resources spent.
- EIP-2028 — reduces the price of Calldata to 16 gas/byte. Respectively, bandwidth grows, scalability improves, and network attack costs rise.
- EIP-2200 — enables the gas reduction model for SSTORE. This allows developers adding new features.
To enter Istanbul, ETH users don’t have to take additional actions, as a rule. The community agreed on the fork so changes are automated. However, some services may ask customers to upgrade clients to continue working with the main network. This happened with Parity, for instance.
Simultaneously, miners and node owners must upgrade clients to maintain the forked chain. Otherwise, they will be unable to process transactions. Finally, developers of ETH smart contracts have to change programs if they’re affected by EIPs. As for now, hundreds of contracts risk becoming obsolete.
Further Ethereum Development
From the very beginning, Ethereum planned to switch to the PoS algorithm. But this evolution is a long and costly process so developers decided to split it into a few phases completed via hard forks, mainly. According to a recently revealed ETH 2.0 roadmap, the network will move through three big upgrades that should introduce PoS, sharding, and eWasm. The successful launch of all EIPs may solve the famous scalability trilemma.
However, the system will go through two smaller changes before the full switch to PoS and launch of ETH 2.0 Phase 0 — Beacon Chain. The first post-Istanbul fork called Muir Glacier will address the issues with the Difficulty Bomb. The second one — Berlin — will introduce the ProgPoW algorithm as a transitional solution before true PoS. Finally, Beacon Chain will mark the beginning of ETH 2.0.
Conclusions
Well, let’s summarize. Istanbul was an essential stage in Ethereum’s global development. It enabled smooth interoperability with Zcash, boosted scalability and privacy, changed gas costs of various operations to keep the network balanced and secure, delivered new opportunities for developers. Moreover, this hard fork was completed with full consensus so the ETH world avoided splits or price fluctuations.
What do you think about Istanbul and further upgrades? Feel free to share your thoughts in our Telegram chat!
