# 0.3.16 (October 6, 2022)
This release of `tracing-subscriber` fixes a regression introduced in
[v0.3.15][subscriber-0.3.15] where `Option::None`'s `Layer`
implementation would set the max level hint to `OFF`. In addition, it
adds several new APIs, including the `Filter::event_enabled` method for
filtering events based on fields values, and the ability to log internal
errors that occur when writing a log line.
This release also replaces the dependency on the unmaintained
[`ansi-term`] crate with the [`nu-ansi-term`] crate, resolving an
*informational* security advisory ([RUSTSEC-2021-0139] for
[`ansi-term`]'s maintainance status. This increases the minimum
supported Rust version (MSRV) to Rust 1.50+, although the crate should
still compile for the previous MSRV of Rust 1.49+ when the `ansi`
feature is not enabled.
### Fixed
- **layer**: `Option::None`'s `Layer` impl always setting the
`max_level_hint` to `LevelFilter::OFF` (#2321)
- Compilation with `-Z minimal versions` (#2246)
- **env-filter**: Clarify that disabled level warnings are emitted by
`tracing-subscriber` (#2285)
### Added
- **fmt**: Log internal errors to `stderr` if writing a log line fails
(#2102)
- **fmt**: `FmtLayer::log_internal_errors` and
`FmtSubscriber::log_internal_errors` methods for configuring whether
internal writer errors are printed to `stderr` (#2102)
- **fmt**: `#[must_use]` attributes on builders to warn if a
`Subscriber` is configured but not set as the default subscriber
(#2239)
- **filter**: `Filter::event_enabled` method for filtering an event
based on its fields (#2245, #2251)
- **filter**: `Targets::default_level` accessor (#2242)
### Changed
- **ansi**: Replaced dependency on unmaintained `ansi-term` crate with
`nu-ansi-term` ((#2287, fixes informational advisory
[RUSTSEC-2021-0139])
- `tracing-core`: updated to [0.1.30][core-0.1.30]
- Minimum Supported Rust Version (MSRV) increased to Rust 1.50+ (when
the `ansi`) feature flag is enabled (#2287)
### Documented
- **fmt**: Correct inaccuracies in `fmt::init` documentation (#2224)
- **filter**: Fix incorrect doc link in `filter::Not` combinator
(#2249)
Thanks to new contributors @cgbur, @DesmondWillowbrook, @RalfJung, and
@poliorcetics, as well as returning contributors @CAD97, @connec,
@jswrenn, @guswynn, and @bryangarza, for contributing to this release!
[nu-ansi-term]: https://github.com/nushell/nu-ansi-term
[ansi_term]: https://github.com/ogham/rust-ansi-term
[RUSTSEC-2021-0139]: https://rustsec.org/advisories/RUSTSEC-2021-0139.html
[core-0.1.30]: https://github.com/tokio-rs/tracing/releases/tag/tracing-core-0.1.30
[subscriber-0.3.15]: https://github.com/tokio-rs/tracing/releases/tag/tracing-subscriber-0.3.15