Rust editions are nothing like C versions. They're orthogonal to language version. They're more like C trigraphs or -W flags. All new Rust features are availab

Rust editions are nothing like C versions. They're orthogonal to language version. They're more like C trigraphs or -W flags. All new Rust features are available from all Rust editions. The 2015 edition has got new features 3 weeks ago, and will get more again in 3 weeks. Old Rust editions are only for backwards compatibility with old source code, e.g. to let it use names that became keywords later.