I'd say the 2018 edition was even more relevant (and that was
late 2018, in fact). Rust was very hard to use prior to non-lexical lifetimes. So the real mass popularity of Rust is very recent.
Also why it's a bit silly to compare Rust to any other language (just pick your favorite: Go, C++, Java/C#, Python/Ruby, Haskell/Elixir, Javascript/TypeScript etc. and expect it to be just as popular. There's a whole lot of legacy projects written in older languages and they have to be maintained, even though some stuff does get ported to Rust in the meantime.)