A major software upgrade to the Ethereum blockchain aimed at drastically reducing its energy usage has been completed, Vitalik Buterin, Ethereum inventor and co-founder tweeted on Thursday. The upgrade, known as the "Merge", will change how transactions on the Ethereum blockchain occur and how ether tokens, the second-largest crypto coin after bitcoin, are created. Under the change, Ethereum will move from a "proof of work" system, in which energy-hungry computers validate transactions by solving complex maths problems, to a "proof of stake" system, where individuals and companies act as validators, using their ether as collateral, to win newly created tokens.

  - Reuters