ETH 2.0 is the upgrade of the Ethereum blockchain aimed at improving scalability, security, and sustainability. It addresses challenges such as network congestion, high transaction fees, and limited scalability in ETH 1.0. 

This upgrade introduces shard chains, allowing parallel processing of transactions to handle more transactions simultaneously, reducing congestion and fees. The transition from Proof of Work to Proof of Stake consensus mechanism improves security and energy efficiency. 

The upgrade also occurs in phases, with the Beacon Chain introduced in Phase 0. Subsequent phases will introduce shard chains and other protocol improvements.

ETH 2.0 is highly anticipated as it promises to unlock new possibilities for decentralized applications and financial services, but it requires community participation and coordination.