The Ropsten testnet – Ethereum’s longest-running testnet – implemented the long-awaited “Merge” with the Beacon chain on Wednesday. The upgrade brings Ethereum one step closer to its long-awaited change to a proof of stake consensus mechanism.
Ropsten allows for development and testing before changes are implemented on the Ethereum mainnet. “The Merge” will be the most significant upgrade ever undergone by Ethereum.
The testnet is identical to Ethereum’s mainnet, but doesn’t put any real funds at risk.
Ethereum core developer Terence Tsao first announced that the configuration for Ropsten’s beacon chain had been merged on May 18th. Client releases began on May 30th, with the full testnet transition slated for today.
The Bellatrix upgrade then successfully launched on June 2nd, as the final upgrade necessary before the full Ropsten merge.
As of 16:09 UST on Wednesday, Ropsten’s proof of work chain reached a terminal total difficulty above 50 quadrillion, and stopped importing blocks on that chain segment.
“Terminal Total Difficulty” refers to a pre-determined difficulty value at which the merge needed to take place.
After that, proof of stake validators began creating blocks on a continuous chain built from the former proof of work history.
Proof of stake is expected to make Ethereum a more energy-efficient blockchain, while also lowering transaction fees substantially. At the moment, high transaction fees have contributed to over one million Ethereum transactions failing every month.