Version
1.63.0 of the Rust language has been released. Changes include the
addition of scoped threads, a new ownership model for raw file descriptors,
and the completion of the borrow-checker transition:

As detailed in this
blog post, we’ve fully removed the previous lexical borrow
checker from rustc across all editions, fully enabling the
non-lexical, new, version of the borrow checker. Since the borrow
checker doesn’t affect the output of rustc, this won’t change the
behavior of any programs, but it completes a long-running migration
(started in the initial stabilization of NLL for the 2018 edition)
to deliver the full benefits of the new borrow checker across all
editions of Rust. For most users, this change will bring slightly
better diagnostics for some borrow checking errors, but will not
otherwise impact which code they can write.

Source: LWN.net – Rust 1.63.0 released