The world’s second-biggest cryptocurrency climbed as high as $1,927 on Thursday, marking its highest level since early June. On Wednesday, ethereum ran its final dry run for the’merge,’ a key event that is expected to make it faster and more energy-efficient. The merge will see ether’s underlying blockchain transition from a proof-of-work system to a more efficient model called proof of-stake. The event, which has been delayed multiple times, is now expected to take place on Sept. 19. The combined value of all cryptocurrencies climbed over $70 billion in a day to $1.2 trillion Thursday, while Bitcoin was up 6% at a price of $24,507, reaching an almost two-week high. . . .