message: Note and in the release notes
diff: # Release 0.2.0 (pending)
  - :warning: [`num-bigint` now requires rustc 1.15 or greater][23].
  +- :warning: [The crate now has a `std` feature, and won't build without it][46].
  + This is in preparation for someday supporting `#![no_std]` with `alloc`.
  - :warning: [The `rand` and `serde` dependencies have been updated to 0.4 and 1.0][24]
  respectively, and neither are enabled by default. The `rustc-serialize`
  crate is no longer supported by `num-bigint`.
  `BitAnd`, `BitOr`, `BitXor`, and `Not`. These act conceptually as if each
  number had an infinite prefix of `0` or `1` bits for positive or negative.
  - [`BigInt` now supports assignment operators][41] like `AddAssign`.
  +- [`BigInt` and `BigUint` now support conversions with `i128` and `u128`][44],
  + if sufficient compiler support is detected.
  - The release also includes other miscellaneous improvements to performance.
  :warning: indicates a **breaking change**.
  [37]: https://github.com/rust-num/num-bigint/pull/37
  [38]: https://github.com/rust-num/num-bigint/pull/38
  [41]: https://github.com/rust-num/num-bigint/pull/41
  +[44]: https://github.com/rust-num/num-bigint/pull/44
  +[46]: https://github.com/rust-num/num-bigint/pull/46
  # Release 0.1.44
  