message: [patch] slipped to 1.21
diff: @@ -734,7 +734,7 @@ source's original crate is replaced.
  More information about overriding dependencies can be found in the [overriding
  dependencies][replace] section of the documentation and [RFC 1969] for the
  technical specification of this feature. Note that the `[patch]` feature will
  -first become available in Rust 1.20, set to be released on 2017-08-31.
  +first become available in Rust 1.21, set to be released on 2017-10-12.
  [RFC 1969]: https://github.com/rust-lang/rfcs/pull/1969
  [replace]: specifying-dependencies.html#overriding-dependencies
  