What is Metropolis (October 2017)?

Metropolis was an upgrade to the Ethereum network that took place in October of 2017. It succeeded Homestead, and was the final phase of Ethereum before the Serenity phase was initiated in 2020. Metropolis delivered a more full-featured user interface by opening the doors for dApp development and tokenization, which in turn fostered the 2017 ICO boom. Throughout Ethereum's history, it has been clear that the continued development of an increasingly scalable, secure blockchain network has been a constant goal — as has an open-source, community-based commitment to governance around the proposal and development processes.