A new Ethereum hard fork, “Muir Glacier,” is about to drop, many months earlier than anticipated.  The network will upgrade when block number 9,200,000 is activated, which block explorer sites Etherscan and Ethernodes predict will be mined on Wednesday, January 2. 

The surprise announcement, which came just before Christmas, angered node operators who will have to prepare for the hard fork during their holiday.

The fork, known as “Muir Glacier,” brings only one improvement, EIP 2384, which delays a ticking time bomb in Ethereum’s Proof-of-Work consensus algorithm known as the “Ice Age.” 

If you use a large exchange (such as Binance or Coinbase), a wallet service (such as Trust Wallet or Coinbase Wallet) or a hardware wallet, (Ledger or Trezor),  you won’t have to lift a finger. But if you’re a node operator or miner, you’ll have to download the latest version of the Ethereum client and update your node to keep playing. 

So what does the update do? 

To keep its Proof-of-Work mechanism running smoothly, the Ethereum network maintains an average block-validation time—between ten and twenty seconds—by manipulating the mining difficulty. Separately, there’s a “difficulty bomb,” which increases the mining complexity every 100,000 blocks. 

If the difficulty bomb increases the problem-solving time too much, it “results in a degradation in the usability of Ethereum due to waiting for confirmation for transactions and Dapps as everything takes longer throughout the network,” explained the so-called Ethereum Cat Herders, the contributors who help coordinate hard forks). In other words, the system can jam and slow to a crawl. 

The new EIP delays the difficulty bomb for another 4,000,000 blocks, or around 611 days, meaning the whole network won’t freeze before Ethereum switch to a Proof-of-Stake consensus mechanism, minimizing any disruption to the network. 

Sooner than expected

Ethereum’s developers had expected that the hard fork would drop later in 2020, but unexpectedly announced the  upgrade two days before Christmas, and said that it would occur on New Year's Day. That irritated a number of node operators who complained that they would have to work over the holidays.  

In addition, the update comes a little over three weeks after Ethereum’s previous hard fork, Istanbul, which occurred on December 7. 

The rationale for the hasty update, according to the Cat Herders, is that Ethereum’s developers got their math wrong. They expected the difficulty bomb would only become an issue in mid-2020, meaning the EIP could be delayed for a while following Istanbul. But “those estimates were wrong,” wrote Hudson Jameson, a developer at Ethereum, in the announcement for the hard fork.

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As described on the webpage Ethereum published for the EIP, researchers noticed the difficulty bomb was having too strong an impact on the network on October 5. They revised their calculations, and estimated that the bomb would accelerate exponentially, meaning the network would see block confirmation times of 20 seconds towards the end of December, and 30 second block times by February. “This will start making the chain bloated and more costly to use,” they wrote. 

Though the upgrade came sooner than expected, it's deja vu all over again for Ethereum node operators and miners. The upgrade is the latest of several delays to the difficulty bomb. Previous delays were implemented through EIP-649 and EIP-1234, which came out in 2017’s Byzantium Hard Fork and 2019’s Constantinople Hard Fork respectively