Ethereum Muir Glacier Upgrade Announcement

A scheduled upgrade at block number 9,200,000 which is predicted to occur on Wednesday, January 1, 2020.

Muir Glacier brings upgrades that will:

• Delay the Difficulty Bomb or Ice Age

Specifically:

EIP-2384 This EIP will only delay the difficulty bomb for another 4,000,000 blocks or approximately 611 days.

Why have a separate upgrade, and why so soon after the last one?

While planning Istanbul, it was first estimated that the bomb would not be noticeable until mid-2020. This implied that it could safely be delayed in the follow-up upgrade to Istanbul. However, those estimates were wrong.

Estimating the added impact from the difficulty bomb on block times shows that we will see 20s block times near the end of December 2019 and 30s+ block times starting February 2020. This will start making the chain bloated and more costly to use.

In order to avoid a delay with the Istanbul upgrade, it has been decided to address the Difficulty Bomb aka Muir Glacier upgrade as a separate one, that only delays the Ice Age. (This answers from Ethereum Cat Herders)

Official announcement: ethereum.org