The Ehtereum mainnet has undergone the Muir Glacier hard fork update, which came three weeks after it completed Istanbul update.
The update, which included only one improvement proposal (EIP 2384) by EthHubs’s Eric Conner in November, was aimed to delay a difficulty bomb for another four million blocks, or about 611 days. It was due to a miscalculation when planning Istanbul, according to Ethereum developer Pooja Ranjan.
The delay bomb, which is a built-in algorithm of the Ethereum blockchain that could increase by far the difficulty in mining a new block if left unaddressed, is the third one undergone by the Ethereum network, as the first two were encountered in 2018 and 2019. It was originally estimated by the developer community to become noticeable in mid-2020, but it became noticeable in October.
Had the Muir Glacier not been implemented, the cost of transactions on the current Ethereum network would have been skyrocketed as block settlement times were to hit 20–30 seconds per block.