Celo developers completed the Ethereum Layer 2 conversion nearly two years after the original proposal, which was originally a separate Layer 1 blockchain and has completed its conversion to the Ethereum Layer 2 network. The official switch on the mainnet took place at around 11pm EST on Tuesday, with the hard fork occurring at block height 31,056,500. Block production for Celo L1 stopped at that point, and the network fully transitioned to Layer 2. The project's core developer, CLabs, first proposed Celo's move from Layer 1 to Layer 2 chain in July 2023. Layer 2 was developed using Optimism's customizable toolkit, the OP Stack. This means Celo now runs as an Optimistic rollup.