The main work included in Phase 0 is around the management of validators and the staking mechanism. In addition, this phase also includes block proposer selection, consensus mechanism rules, and a reward/penalty mechanism.
Phase 1 includes the development of shard chains and blocks along with the cross-linking (anchoring) of shard blocks to the beacon chain (the core system chain).
Phase 1.5 also known as "the merge" is where ethereum mainnet will transit into Ethereum 2 most likely by becoming a shard chain of Ethereum 2.0.
The next stage, Phase 2, is focused on execution environment upgrades, and includes a VM upgrade to ewasm along with cross-shard communication and access to execution environments. Moreover, Phase 2 introduces the ability to run and interact with smart contracts. Currently, the specification is not final and might...