Muir Glacier hard fork
Mainnet 2020-01-02
The difficulty bomb was delayed.
What changed
- Users
- The difficulty bomb is a mechanism that artificially raises mining difficulty over time to lengthen block intervals. From late 2019 it kicked in again, blocks started coming out slower than usual, and transaction confirmations were delayed accordingly. Muir Glacier pushed the bomb's activation back by 4 million blocks. As a result, block intervals returned to their original pace and transactions were processed as usual. There were no visible changes such as wallet features or fee structure.
- Wallet & app developers
- Nothing changed directly. This fork contained only EIP-2384 and did not change any opcodes, transaction formats, or fee rules. The only difference was that, with block intervals back to normal, contracts and apps that behaved based on block count or time worked as expected. Because it followed the earlier Istanbul fork by a month, support for both forks had to be checked together.
- Node operators
- Before the fork block, clients had to be upgraded to a version that supports Muir Glacier. Nodes that did not upgrade followed a different chain after the fork and dropped off the network. For mining nodes, the difficulty formula changed, the artificially rising difficulty disappeared, and they produced blocks at the normal interval again. There were no other changes to storage or sync methods.
Key EIPs
- EIP-2384 Muir Glacier difficulty bomb delay