v9.1.1

• [Build] Change man page generation path to resolve issue with cargo publish.

v9.1.0

• [Improvement] Add --keep display equivalent to --strip safe.
• [Improvement] Add modified zeng palette sorting method, improving optimization of indexed images.
• [Improvement] If only one filter is specified, guarantee to only use this one.
• [Improvement] Evaluate low-depth indexed even if low-depth grayscale was already achieved.
• [Bugfix] Fix battiato palette sorting method not being used if the input was not already indexed.
• [Bugfix] Fix rare crash caused by a truncated palette.
• [Build] Reduce size of binaries.
• [Build] Add man page generation.
• [Build] Publish deb archives for Linux.
• [Misc] Bump minimum Rust version to 1.74.0.

⚠️ Due to a build issue, this release is not available on crates.io.

v9.0.0

• [Breaking] Remove --backup option. Use --out or --dir to preserve existing files.
• [Breaking] Remove --check option. Use --nx --nz to perform a non-optimizing run.
• [Breaking] API: Replace pretend option with OutFile::None.
• [Breaking] API: Move preserve_attrs into OutFile::Path.
• [Breaking] Default to removing interlacing. Use -i keep to retain existing interlacing.
• [Feature] Add Raw API for creating optimised PNGs from raw image data.
• [Feature] Add basic support for APNG files.
• [Feature] Add --scale16 option to forcibly reduce 16-bit images to 8-bit.
• [Improvement] Process multiple files in parallel.
• [Improvement] Improve reductions, particularly for indexed or very small images.
• [Improvement] Improve compression with latest version of libdeflate.
• [Improvement] Recompress iCCP chunks.
• [Improvement] Change recursive mode to only process .png/.apng files.
• [Improvement] Add support for glob patterns in quotes on Windows.
• [Improvement] Quieter default output logging, with multiple levels of verbosity.
• [Bugfix] Fix deadlock when using oxipng within an existing Rayon thread pool.
• [Bugfix] Fix early abort in recursive mode when a read error occurred.
• [Bugfix] Fix losing aux chunks when there's more than one of the same type.
• [Bugfix] Fix sometimes writing output even when it was larger.
• [Misc] Revamp CI workflow to upload artifacts and generate binaries for additional architectures.
• [Misc] Bump minimum Rust version to 1.66.0.

v8.0.0

• [Breaking] Revamp alpha optimization
• [Bugfix] Fix grayscale depth reduction with tRNS pixel
• [Bugfix] Fix fast mode with zopfli
• [Improvement] Tweaks to interlacing and format display
• [Improvement] Ability to reduce alpha channel to tRNS pixel
• [Improvement] Performance improvements to colorspace reduction
• [Misc] Disable image validation in release mode, as it is deemed no longer necessary

v7.0.0

• [Breaking] Switch to libdeflater as the default
• [Breaking] Rebalance presets
• [Breaking] Update safe headers to remove
• [Breaking] Bump minimum Rust version to 1.61.0
• [Feature] Introduce new filter strategies
• [Feature] Allow setting libdeflate compression level
• [Feature] Add optional dockerization
• [Improvement] Improve alpha reductions
• [Improvement] Fast deinterlace for 8-bit
• [Improvement] Refactor heuristics for fast filter evaluation
• [Improvement] Improve file size reduction further
• [Bugfix] Avoid printing output bytes on decompress error
• [Bugfix] Fix compression level 0
• [Bugfix] Fix directional alpha reductions
• [Bugfix] Fix edge cases in palette reduction

v6.0.1

• [Bugfix] Fix an issue where Zopfli mode could generate corrupt images

v6.0.0

• [Breaking] Bump minimum Rust version to 1.57.0
• [Feature] Add --check/-c CLI option
• [Security] Update stderrlog to 0.5.2 (Fixes RUSTSEC-2022-0006)
• [Security] Remove chrono as a transitive dependency (Fixes RUSTSEC-2020-0159)
• [Misc] Bump clap to 3.2
• [Misc] Bump zopfli to 0.7
• [Misc] Bump libdeflater to 0.10
• [Misc] Remove byteorder dependency in favor of stdlib functions
• [Misc] Bump image to 0.24
• [Misc] Bump crc to 3.0
• [Misc] Bump miniz_oxide to 0.6
• [Misc] Update to Rust edition 2021
• [Misc] Various internal improvements

v5.0.1

Version 5.0.1

v5.0.0

• [Breaking] Bump minimum Rust version to 1.46.0
• [Bugfix] Avoid many panics that may occur on broken files
• [Bugfix] Fix race condition that may cause tests to fail
• [Performance] Optimizations to unfiltering and copying
• [Feature] Add --ng option to skip grayscale reduction
• [Feature] Also preserve timestamps when using --preserve
• [Misc] Bump crc to 2.x

v4.0.3

• Bump itertools to 0.10.x
• Temporarily disable i686 releases, which were failing due to an odd linker issue,
  so that at least amd64 builds will publish successfully
  • This only relates to the releases published on Github. You can still manually compile oxipng for any platform.