Development of Ethereum

The Shanghai Upgrade brought staking withdrawals to the execution layer, which allows stakers to withdraw their ETH from the Beacon Chain to the execution layer.

The Capella Upgrade was the third major upgrade to the consensus layer (Beacon Chain). It occurred synchronously with Shanghai Upgrade, the execution layer upgrade, to enable staking withdrawals. This upgrade also provided automatic account sweeping functionality, which continuously processes validator accounts for any available rewards payments or full withdrawals.

Starting from Paris, Ethereum moved towards The Merge. It switched off the proof-of-work (PoW) algorithm and associated consensus logic and switched on proof-of-stake (PoS).

The Bellatrix Upgrade was the second scheduled upgrade for the Beacon Chain, preparing the chain for The Merge. It brings validator penalties to their full values for inactivity and slashable offenses. Bellatrix also includes an update to the fork choice rules to prepare the chain for The Merge and the transition from the last proof-of-work (PoW) block to the first proof-of-stake (PoS) block.

The Gray Glacier Upgrade pushed back the difficulty bomb by three months. This is the only change introduced in this upgrade, and is similar in nature to the Arrow Glacier and Muir Glacier upgrades. Similar changes have been performed on the Byzantium, Constantinople, and London Upgrades.

The Arrow Glacier Upgrade pushed back the difficulty bomb by several months. This is the only change introduced in this upgrade, and is similar in nature to the Muir Glacier Upgrade. Similar changes have been performed on the Byzantium, Constantinople, and London Upgrades.

The Altair Upgrade was the first scheduled upgrade for the Beacon Chain. It added support for "sync committees" — enabling light clients, and increased validator inactivity and slashing penalties as development progressed towards The Merge.

The London Upgrade introduced EIP-1559, which reformed the transaction fee market, along with changes to the Gas refund handling and the Ice Age schedule.

The Berlin Upgrade optimized Gas costs of certain actions in the EVM and added support for multiple transaction types.

The Beacon Chain needed 16,384 deposits of 32 staked ETH to ship securely. The chain started producing blocks on December 1, 2020. This is an important first step in achieving the Ethereum vision.

The Muir Glacier Upgrade introduced a delay to the difficulty bomb, which solved the usability issue of Ethereum caused by increased block difficulty under the PoW mechanism, which would result in longer transaction times and increased waiting times for using DApps.

The Istanbul version optimized Gas costs in the EVM, improved denial-of-service (DoS) attack resilience, and allowed contracts to introduce more creative functions.

The Constantinople version optimized Gas costs in the EVM and added the ability to interact with addresses that haven't been created yet.

The Byzantium version reduced block rewards to 3 ETH and delayed the difficulty bomb by a year. It added new features and some cryptography methods to allow Layer 2 scalability.

The Spurious Dragon Upgrade was the second response to the denial-of-service (DoS) attacks on the network.

The Tangerine Whistle Upgrade was the first response to the denial-of -service (DoS) attacks on the network.

The DAO Fork was in response to the 2016 DAO attack where an insecure DAO contract was drained of over 3.6 million ETH in a hack. This course of action was voted on by the Ethereum community and over 85% of the votes were for the fork. Some miners refused and went on to form Ethereum Classic.

The Homestead version included several protocol changes and a networking change that gave Ethereum the ability to do further network upgrades.

The Frontier Thawing Upgrade lifted the 5,000 Gas limit per block, which means the maximum Gas limit reached 21,000 units. It also set the default Gas price to 51 Gwei. The difficulty bomb was introduced to ensure a future hard fork to proof-of-stake (PoS).

Ethereum officially went live on July 30, 2015, with Frontier being the initial version of Ethereum.