The Berlin hard fork will happen on the Ropsten testnet on block 9812189, which should be mined around 2021-03-10 21:45:00 UTC. Due to the decision to disable EIP-2315 from the Berlin fork rather late in the process, fully compatible clients were not released until very close to this deadline. As such, we expect a large number of Ropsten miners to continue to mine the pre-Berlin chain, which may lead to multiple competing forks. This may lead to an increase in reorgs or other consensus issues during this time period. As such, we suggest you limit testing on the Ropsten testnet to consensus-related issues until the Berlin chain is firmly established.