This standard solves some of the shortcomings of ERC20 while maintaining backward compatibility with ERC20. It avoids the problems and vulnerabilities of EIP223.
It goes a step further by allowing operators (generally contracts) which can manage the tokens in the same way that the ERC20 with infinite approve was allowed. Finally, it adds hooks to provide further control to token holders over their tokens. Note that, the usage of ERC820 provides backward compatibility with wallets and existing contracts without having to be redeployed thanks proxy contracts implementing the hooks.
https://eips.ethereum.org/EIPS/eip-777So this standard corrects errors of the ERC20 standard, but is it compatible with decentralized exchanges?