Back in July, Jordi Baylina, Jacques Dafflon, and Thomas Shababi made waves when they announced their EIP for a new token standard, ERC777, was approaching last call. This has not happened yet. However, as of today, ERC820 has.
ERC820, subtitled "pseudo-introspection using a registry," describes an EDCC (also known as a smart contract) that allows addresses to register publicly accessible information about the functionality of other EDCCs. The purpose of this registry is specifically for ERC777 tokens, which rely upon it to function.
ERC777-based tokens will be able to do things not currently possible with ERC20-based tokens, including more customizable coding. ERC777-based tokens will allow for the holder or EDCC-creator to program certain functions, like subscription payments, transaction receipts, or charitable donations.
However, not all EDCCs will necessarily be compatible with ERC777 tokens. The token, then, needs to "know" whether a particular contract is compatible before interacting with it. ERC820 is designed so that ERC777-based tokens can access this knowledge.
The last call period lasts a minimum of two weeks, during which time community feedback is encouraged. If no one raises any pressing concerns, then the Ethereum Improvement Proposal (of which ERCs are one type) will be finalized.