The planned Istanbul hard fork on the Ethereum network has officially taken place. The update occurred on block #9069000 at 00:25:09 GMT on Sunday, December 8th.
The block on which the hard fork took place found the Chinese mining pool SparkPool.
Congrats to @sparkpool_eth for mining the Istanbul fork block!— vitalik.eth (@VitalikButerin) December 8, 2019
The upgrade was designed to ensure Ethereum compatibility with Zcash cryptocurrency, increase the scalability of solutions based on zero-disclosure proof technology (SNARKs and STARKs), change the cost of gas for various operating codes (opcodes) in order to complicate spam blocks and increase the network's resistance to DoS attacks.
As previously reported, most Parity and Geth clients were still not ready for this massive upgrade.
At the time of the update, the overall availability of the network was slightly less than 50%.
The second part of the upgrade (Berlin) is expected to happen before the end of June 2020. It should include proposals that require more time for testing, for example, EIP-1057, a considerable controversy, a modified ProgPoW mining algorithm aimed at reducing the influence of ASIC devices. Note, that during the development of the update, 6 EIP have already been approved.
Ultimately, as the developers hope, upon completion of both parts of the upgrade, the Ethereum network will become faster, cheaper, and more scalable. They expect all this to be achieved without compromising the decentralization and flexibility of the network.