Ethereum Byzantium update will be held on October 17

Ethereum is preparing to make an important hardfork called Byzantium which, despite recent spam attacks against the testnet where it was being tested, will be carried out as scheduled on 17 October.

The most popular client in the network, Go Ethereum (Geth), made changes to its code to reinforce this set of updates. From block number 4,370,000, Byzantium will be activated, and it is imperative that users update their nodes to be able to remain active in the blockchain.

Geth's decision is significant because it ensures that the hardfork is performed throughout the network, because it represents about 70% percent of the Ethereum nodes. The developers working at Geth are sponsored by the Ethereum Foundation, which manages the development of the network.

The update is part of the roadmap established earlier this year. After a discussion of the core developer team Ethereum, held on September 22, and despite the attack on the Ropsten test network, the activation of Byzantium will be done smoothly.

Through Reddit, Geth has asked users of their nodes to update their software to the Ptolemy version or v1.7.1, on time, and even with a period in advance and thus allow a "smooth transition" as set out in the launch ad on GitHub. It should be noted that the previous versions will be incompatible with the network after Byzantium, so this is an important moment for the network.

It also used the forum developer Peter Szilágyi urging users to update a week in advance, ensuring that these are non-trivial updates, and clarified that this is a decision of Geth, and that other teams will give their own guidelines.
If you are using Geth directly, just update it on time (at least a week before on the main network). If you are using Mist, I assume they will create and send your update in the next few days.

Peter Szilágyi
Developer, Ethereum
ATTACK TO ROPSTEN MADE CHANGE THE BYZANTIUM TESNET
However, despite the fact that until now ensures that there will be no delay in the application of hardfork, the truth is that the spam attack suffered by the testnet Ethereum caused the tests of this update migrate to Rinkeby, where there are older levels but does not offer the same characteristics as Ropsten, especially in terms of consensus tests.

This network links the transactions made in the tesnet to the accounts of GitHub of the developers, reason why an attack could not be anonymous. Geth was one of the most important users of this test network.