During an Ethereum Core Developers Meeting on September 22, 2017, a tentative date for the Byzantium update was revealed.
In conversation, Ethereum core developers Hudson Jameson, Péter Szilágyi, Ethereum founder Vitalik Buterin, and others revealed that Byzantium upgrades will be implemented around October 17. Part of a larger, multi-component upgrade of Byzantium code will be enforced at block 4,370,000 – or in about four days according to current metrics – as a hard fork. A common (yet controversial) strategy for upgrading blockchains, this means the changes are required to be accepted broadly by all stakeholders on the ethereum blockchain. In total, the changes are designed to make the platform lighter and faster to run, improving transaction speed, smart contract security and eventually perhaps, privacy.
Initial stages of the Byzantium hard fork were tested on the Ethereum Ropsten test network as of block number 1,700,000 on September 17, 2017. Days later, the developers doubled the rewards for certain bug bounties related to the release. As developers hitherto mentioned, the increased bounty would extend until the mainnet hard fork. With a date in hand, testers have been effectively issued a deadline.
There will be hardforks, but unlike Bitcoin or Ethereum Classic, there isn’t controversy about these protocol upgrades. Everybody is excited and generally happy about them, so there shouldn’t be a valid continuation of the Ethereum blockchain other than the new fork. You don’t need to do anything unless you’re mining or running node software, in which case you need to get updates when they are out.