amounts of ether to different addresses, and a block reward of 5 ETH. Since the initial launch, Ethereum has undergone a number of planned protocol upgrades, which are important changes affecting the underlying functionality and/or incentive structures of the platform. Protocol upgrades are accomplished by means of a hard fork. In 2016, a decentralized autonomous organization called The DAO—a set of smart contracts developed on the platform—raised a record in a crowd sale to fund the project. The DAO was exploited in June 2016 when of DAO tokens were stolen by an unknown hacker. The event sparked a debate in the crypto-community about whether Ethereum should perform a contentious "hard fork" to reappropriate the affected funds. The fork resulted in the network splitting into two blockchains: Ethereum with the theft reversed, and Ethereum Classic which continued on the original chain. The hard fork created a rivalry between the two networks. After the hard fork, Ethereum subsequently forked twice in the fourth quarter of 2016 to deal with other attacks. Continued development and milestones (2017–present) In March 2017, various blockchain startups, research groups, and Fortune 500 companies announced the creation of the Enterprise Ethereum Alliance (EEA) with 30 founding members. By May 2017, the nonprofit organization had 116 enterprise members, including ConsenSys, CME Group, Cornell University's research group, Toyota Research Institute, Samsung SDS, Microsoft, Intel, J. P. Morgan, Cooley LLP, Merck KGaA, DTCC, Deloitte, Accenture, Banco Santander, BNY Mellon, ING, and National Bank of Canada. By July 2017, there were over 150 members in the alliance, including MasterCard, Cisco Systems, Sberbank, and Scotiabank. By January 2018, ether was the second-largest cryptocurrency in terms of market capitalization, behind bitcoin. , it maintained that relative position. After the Constantinople upgrade on 28 February 2019, there were two network upgrades made within a month late in the year: Istanbul on 8 December 2019 and Muir Glacier on 2 January 2020. In 2019, Ethereum Foundation employee Virgil Griffith was arrested by the US government for presenting at a blockchain conference in North Korea. He would later plead guilty to one count of conspiring to violate the International Emergency Economic Powers Act in 2021. In March 2021, Visa Inc. announced that it began settling stablecoin transactions using Ethereum. In April 2021, JP Morgan Chase, UBS, and MasterCard announced that they were investing into ConsenSys, a software development firm that builds Ethereum-related infrastructure. There were two network