(FILES) This file illustration photo taken in London on May 08, 2022, shows a gold plated souvenir cryptocurrency Tether (USDT) coin arranged beside a screen displaying a trading chart. Tether (USDT) is an Ethereum token known as a stablecoin that is pegged to the value of the US dollar. - Leading cryptocurrency figures hailed on on September 15, 2022, the completion of one of the biggest software upgrades the sector has ever attempted, an overhaul of the Ethereum blockchain aimed at reducing its massive energy consumption. Developers had spent years working on an energy-efficient version of Ethereum, a digital ledger that underpins tens of billions of dollars worth of cryptocurrencies, digital tokens (NFTs), games and apps. (Photo by Justin TALLIS / AFP)