Small correction; we discovered before merging the PR #4333 that block/generation times had drifted slightly. (This is entirely normal, generation lengths are probabilistic, and fluctuations in mining power or just randomness will move them around.)
Therefore, we adjusted the Mainnet protocol upgrade height to 941700 as you can see in the PR.
About 30 minutes ago the Aeternity Testnet upgraded to the Ceres protocol. It seems to have gone pretty frictionless, though the explorer https://testnet.aescan.io/ and the middleware seems to have a few smaller problems displaying correct information regarding auction lengths - this is currently being investigated!
We invite everyone to interact with the Testnet as much as possible now, to shake out any remaining inconsistencies before it is time for the Mainnet to upgrade (May 7th). Please report issues here in the forum or in Github issues! Happy testing!