[mlindner]

There's no such thing as a "too current a version of rust". All Rust compilers (since 1.0) compile all previous versions of code and will continue to do so.

In the rare case you might hit something that was removed/modified because of a security exploit, but those are very very rare.

[edflsafoiewq]

This is not true in practice. Old code has failed to compile for various reasons; off the top of my head, new additions to the prelude, and denied lints that became more restrictive. It's not super rare.