September Release
The Metropolis update to Ethereum is set to become active in late September/October. This is the third major release of the Ethereum blockchain, with the previous being Homestead in 2016. This update requires a hardfork, and is expected to go over smoothly, with no support for the legacy chain remaining afterward.
It's rare that a legacy chain is kept alive, as chain splits are usually a result of much planning and majority consensus. The recent Bitcoin Cash / Bitcoin hard fork is a prime example of an outlier case, in which the community was divided during a hardfork, thus keeping both chains alive.
What Makes Metropolis Special
One of the key features that makes Metropolis so exciting is the implementation of zk-SNARKS. This technology has been implemented by other blockchains, and allows for the eventual introduction of anonymous transactions, something that some other blockchains are already able to do. More information about zk-SNARKS can be found here, although the explanation is extremely technical.
The Metropolis update is heavily anticipated by the Ethereum community, and will likely cause the price to rise drastically in the days or weeks leading up to it. It's entirely possible that Ethereum will break through its all time high of $420.
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