The Ethereum mainnet has just undergone the Muir Glacier hard fork, less than a month after its Istanbul update on Dec. 8.
The Muir Glacier update was activated at Block number 9,200,000 on Jan. 2, 2020, with only one improvement proposal, EIP 2384. The proposal aims to delay the difficulty bomb, a built-in algorithm of the Ethereum blockchain that could drastically increase the difficulty in mining a new block if left unaccounted for. The update is designed to delay the difficulty bomb for another 4,000,000 blocks, or approximately 611 days.
This is the third difficulty bomb delay the Ethereum network has undergone, with the first two occurred in 2018 and 2019. The Muir Glacier update, which took place three weeks after the last update Istanbul, was due to a miscalculation when planning Istanbul, said Ethereum developer Pooja Ranjan in a Medium post. The developer community initially estimated the difficulty bomb to become noticeable in mid-2020. However, instead, the bomb became noticeable in October, forcing the community to address the issue sooner than planned.
Some developers have voiced concerns over the difficulty bomb, asking for a removal of this algorithm completely. However, given the short time frame, the developer team eventually decided to move forward with another delay, Ranjan stated.
Besides the mainnet, the Ropsten testnet also deployed the same update at block number 7117117, while other Ethereum testnets remain unchanged.