A new Ropsten Beacon Chain was launched on May 30 to provide consensus to the network and will upgrade to merge-compatible Bellatrix protocol on June 2. The next day miners will determine the metric known as the Terminal Total Difficulty (TTD) that measures the computing power needed to verify transactions on a blockchain. The node operators will then need to manually update their clients with the announced value.
“After the Ropsten transition, two more testnets (Goerli and Sepolia) will be transitioned to proof-of-stake before focus shifts to mainnet. Other testnets, such as Rinkeby and Kovan, may be maintained and upgraded separately by the community but will no longer be monitored by client developers,” Ethereum’s developer Tim Beiko announced in the blog post.
Given that there are no issues with Ropsten, other testnets will go through the Merge. Once Goerli and Sepolia transition successfully and become stable, developers will determine the slot height for the Bellatrix upgrade on Beacon Chain and TTD for the mainnet transition. Only after these steps, it will be possible to estimate the exact date of the Merge, although any found issues can postpone the long-awaited transition.