For what is worth, you can use https://lib.rs to see the earliest version a crate supports. For Rust 1.63.0, you will have to rely on Clap 4.0.32 from December 2022, instead of anything newer (which only support 1.64.0+): https://lib.rs/crates/clap/versions

For anstream, the situation seems more difficult for you, as it doesn't seem that there's any (non-yanked?) release that supports <1.64.0: https://lib.rs/crates/anstream/versions