Rust editions (2015, 2018, 2021) are periodic updates to the language that introduce new features and syntax improvements without breaking existing code, while 2024 is not yet a released edition. You specify the edition in your project's Cargo.toml file to enable these features.
[package]
edition = "2021"
The 2021 edition is the current stable default and includes improvements like let chains and better async support. The 2018 edition introduced use statements and async/await syntax, while 2015 was the initial edition. Always use the latest stable edition for new projects unless you have a specific compatibility requirement.