A launch date for the ‘Byzantium’ testnet, the next critical step toward a major upgrade for ethereum, has been announced.

The testnet will be deployed on September 18, following a discussion between ethereum core developers today. Byzantium is the first of two phases in the ‘Metropolis‘ update, set to be followed by ‘Constantinople’ at a later time.

The actual network upgrade release will likely be launched in early October, depending on the length of the testing period and any issues that may arise during that time. Observers had predicted that the Metropolis upgrade could come as early as this month, but ongoing development pushed that date to later in the fall.

As developer Hudson jameson, the unofficial release manager for Metropolis, said during the meeting:

“For all the coin media that keep saying September – it’s not September. It’s October 9 unless something goes wrong with the testnet.”

Vitalik Buterin, the creator of ethereum, said during the meeting that he anticipates the Byzantium test phase will last between three and four weeks.

In response, developer Péter Szilágyi posited that the timeline for that could shift, noting “if things go wrong….they will go wrong fast.”

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