Celo has launched a layer-2 testnet called "Dango" on Ethereum, which is a fork of the Alfajores testnet. "Dango" allows for the bridging of WETH and ERC-20 tokens between Ethereum and Celo, introduces the concept of CELO token duality, and maintains key layer-1 features like Fee Abstraction and SocialConnect. The Alfajores testnet will be directly migrated for dApp developers to test once infrastructure providers have updated for the layer-2 integration.