Changelog

This page documents the recent changes and version history for Zstandard.

​

v1.6.0 (Dec 2025)

• API: Legacy format support is now disabled by default
• Build: ZSTD_LEGACY_SUPPORT defaults to 0 in Makefile and CMake

​

v1.5.7 (Feb 2025)

​

Fixes

• Fix: Compression bug in 32-bit mode associated with long-lasting sessions

​

API

• New: Method ZSTD_compressSequencesAndLiterals() (#4217, #4232)
• Enhancement: ZSTD_getFrameHeader() works on skippable frames (#4228)

​

Performance

• Perf: Substantial compression speed improvements (up to +30%) on small data, by @TocarIP (#4144) and @cyan4973 (#4165)
• Perf: Improved compression speed (~+5%) for dictionary compression at low levels (#4170)
• Perf: Much faster speed for --patch-from at high compression levels (#4276)
• Perf: Higher --patch-from compression ratios, notably at high levels (#4288)
• Perf: Better speed for binaries on Windows (@pps83) and when compiled with Visual Studio (@MessyHack)
• Perf: Slight compression ratio improvement thanks to better block boundaries (#4136, #4176, #4178)
• Perf: Slight compression ratio improvement for dfast, aka levels 3 and 4 (#4171)
• Perf: Runtime bmi2 detection enabled on x86 32-bit mode (#4251)

​

CLI

• New: Multi-threading as default CLI setting, by @daniellerozenblit
• New: --max command (#4290)

​

Build

• Enhancement: Improve msbuild version autodetection, support VS2022, by @ManuelBlanc
• Fix: meson build by @artem and @Victor-C-Zhang, and on Windows by @bgilbert
• Enhancement: Compatibility with Apple Framework, by @Treata11
• Enhancement: Improve icc/icx compatibility, by @josepho0918 and @luau-project
• Enhancement: Improve compatibility with Android NDK, by Adenilson Cavalcanti

​

Portability

• Enhancement: Linux kernel branch, with improved support for Sequence producers (@embg, @gcabiddu, @cyan4973)
• Enhancement: Improved qnx compatibility, suggested by @rainbowball
• Enhancement: Improved install script for FreeBSD, by @sunpoet
• Fix: Test suite compatibility with gnu hurd, by @diegonc

​

Documentation

• Enhancement: Clarify specification, by @elasota

​

Miscellaneous

• Enhancement: Improved tests/decodecorpus validation tool (#4102), by antmicro

​

v1.5.6 (Mar 2024)

​

API

• Promotion: ZSTD_c_targetCBlockSize to Stable API by @felixhandte
• New: ZSTD_d_maxBlockSize experimental parameter, to reduce streaming decompression memory, by @terrelln

​

Performance

• Perf: Improve performance of param ZSTD_c_targetCBlockSize, by @Cyan4973
• Perf: Improved compression of arrays of integers at high compression, by @Cyan4973

​

Library

• Enhancement: Reduce binary size with selective build-time exclusion, by @felixhandte
• Perf: Improved huffman speed on small data and linux kernel, by @terrelln
• Enhancement: Accept dictionaries with partial literal tables, by @terrelln
• Fix: CCtx size estimation with external sequence producer, by @embg
• Fix: Corner case decoder behaviors, by @Cyan4973 and @aimuz
• Fix: Zdict prototype mismatch in static_only mode, by @ldv-alt
• Fix: Several bugs in magicless-format decoding, by @embg

​

CLI

• New: Add common compressed file types to --exclude-compressed by @daniellerozenblit
• Fix: Mixing -c and -o commands with --rm, by @Cyan4973
• Fix: Erroneous exclusion of hidden files with --output-dir-mirror by @felixhandte
• Enhancement: Improved time accuracy on BSD, by @felixhandte
• Enhancement: Better errors on argument parsing, by @KapJI

​

Tests

• Enhancement: Better compatibility with older versions of grep, by @Cyan4973
• Enhancement: Lorem ipsum generator as default backup content, by @Cyan4973

​

Build

• Enhancement: CMake improvements by @terrelln, @sighingnow, @gjasny, @JohanMabille, @Saverio976, @gruenich, @teo-tsirpanis
• New: Bazel support, by @jondo2010
• Fix: Cross-compiling for AArch64 with lld by @jcelerier
• Fix: Apple platform compatibility, by @nidhijaju
• Fix: Visual 2012 and lower compatibility, by @Cyan4973
• Enhancement: Improve win32 support, by @DimitriPapadopoulos
• Enhancement: Better C90 compliance for zlibWrapper, by @emaste

​

Portability

• New: Fat binaries on macos, by @mredig
• New: ARM64EC compatibility for Windows, by @dunhor
• New: QNX support by @klausholstjacobsen
• Enhancement: MSYS2 and Cygwin makefile installation and test support, by @QBos07
• Enhancement: RISC-V support validation in CI, by @Cyan4973
• Enhancement: Sparc64 support validation in CI, by @Cyan4973
• Enhancement: AIX compatibility, by @likema
• Enhancement: HP-UX compatibility, by @likema

​

Documentation

• Enhancement: Improved specification accuracy, by @elasota

​

Bug Fixes

• Fix: Fix and deprecate ZSTD_generateSequences (#3981)

​

v1.5.5 (Apr 2023)

​

Fixes

• Fix: Rare corruption bug affecting the high compression mode, reported by @danlark1 (#3517, @terrelln)

​

Performance

• Perf: Improve mid-level compression speed (#3529, #3533, #3543, @yoniko and #3552, @terrelln)

​

Library

• Deprecation: Bufferless block-level API (#3534) by @terrelln

​

CLI

• Enhancement: Mmap large dictionaries to save memory, by @daniellerozenblit
• Perf: Improve speed of —patch-from mode (~+50%) (#3545) by @daniellerozenblit
• Perf: Improve i/o speed (~+10%) when processing lots of small files (#3479) by @felixhandte
• Fix: Zstd no longer crashes when requested to write into write-protected directory (#3541) by @felixhandte
• Fix: Decompression into block device using -o, reported by @georgmu (#3583)

​

Build

• Fix: Zstd CLI compiled with lzma support but not zlib support (#3494) by @Hello71
• Fix: CMake does no longer require 3.18 as minimum version (#3510) by @kou
• Fix: MSVC+ClangCL linking issue (#3569) by @tru
• Fix: zstd-dll, version of zstd CLI that links to the dynamic library (#3496) by @yoniko
• Fix: MSVC warnings (#3495) by @embg

​

Documentation

• Enhancement: Updated zstd specification to clarify corner cases, by @Cyan4973
• Enhancement: Document how to create fat binaries for macos (#3568) by @rickmark

​

Miscellaneous

• Perf: Improve seekable format ingestion speed (~+100%) for very small chunk sizes (#3544) by @Cyan4973
• Enhancement: tests/fullbench can benchmark multiple files (#3516) by @dloidolt

​

v1.5.4 (Feb 2023)

​

Performance

• Perf: +20% faster huffman decompression for targets that can’t compile x64 assembly (#3449, @terrelln)
• Perf: Up to +10% faster streaming compression at levels 1-2 (#3114, @embg)
• Perf: +4-13% for levels 5-12 by optimizing function generation (#3295, @terrelln)
• Perf: +3-11% compression speed for arm target (#3199, #3164, #3145, #3141, #3138, @JunHe77 and #3139, #3160, @danlark1)
• Perf: +5-30% faster dictionary compression at levels 1-4 (#3086, #3114, #3152, @embg)
• Perf: +10-20% cold dict compression speed by prefetching CDict tables (#3177, @embg)
• Perf: +1% faster compression by removing a branch in ZSTD_fast_noDict (#3129, @felixhandte)
• Perf: Small compression ratio improvements in high compression mode (#2983, #3391, @Cyan4973 and #3285, #3302, @daniellerozenblit)
• Perf: Small speed improvement by better detecting STATIC_BMI2 for clang (#3080, @TocarIP)
• Perf: Improved streaming performance when ZSTD_c_stableInBuffer is set (#2974, @Cyan4973)

​

CLI

• New: Asynchronous I/O for improved cli speed (#2975, #2985, #3021, #3022, @yoniko)
• Change: zstdless behavior to align with zless (#2909, @binhdvo)
• Enhancement: Keep original file if -c or --stdout is given (#3052, @dirkmueller)
• Enhancement: Keep original files when result is concatenated into a single output with -o (#3450, @Cyan4973)
• Enhancement: Preserve Permissions and Ownership of regular files (#3432, @felixhandte)
• Enhancement: Print zlib/lz4/lzma library versions with -vv (#3030, @terrelln)
• Enhancement: Print checksum value for single frame files with -lv (#3332, @Cyan4973)
• Enhancement: Print dictID when present with -lv (#3184, @htnhan)
• Enhancement: When stderr is not the console, disable status updates, but preserve final summary (#3458, @Cyan4973)
• Enhancement: Support --best and --no-name in gzip compatibility mode (#3059, @dirkmueller)
• Enhancement: Support for posix high resolution timer clock_gettime(), for improved benchmark accuracy (#3423, @Cyan4973)
• Enhancement: Improved help/usage (-h, -H) formatting (#3094, @dirkmueller and #3385, @jonpalmisc)
• Fix: Better handling of bogus numeric values (#3268, @ctkhanhly)
• Fix: Input consists of multiple files and stdin (#3222, @yoniko)
• Fix: Tiny files passthrough (#3215, @cgbur)
• Fix: -r on empty directory (#3027, @brailovich)
• Fix: Empty string as argument for --output-dir-* (#3220, @embg)
• Fix: Decompression memory usage reported by -vv --long (#3042, @u1f35c, and #3232, @zengyijing)
• Fix: Infinite loop when empty input is passed to trainer (#3081, @terrelln)
• Fix: --adapt doesn’t work when --no-progress is also set (#3354, @terrelln)

​

API

• New: Support for Block-Level Sequence Producer (#3333, @embg)
• New: Support for in-place decompression (#3432, @terrelln)
• New: ZSTD_CCtx_setCParams() function, set all parameters defined in a ZSTD_compressionParameters structure (#3403, @Cyan4973)
• Enhancement: Streaming decompression detects incorrect header ID sooner (#3175, @Cyan4973)
• Enhancement: Window size resizing optimization for edge case (#3345, @daniellerozenblit)
• Enhancement: More accurate error codes for busy-loop scenarios (#3413, #3455, @Cyan4973)
• Fix: Limit overflow in compressBound and decompressBound (#3362, #3373, Cyan4973) reported by @nigeltao
• Deprecation: Several advanced experimental functions: streaming (#3408, @embg), copy (#3196, @mileshu)

​

Bug Fixes

• Fix: Corruption that rarely occurs in 32-bit mode with wlog=25 (#3361, @terrelln)
• Fix: Block-splitter (#3033, @Cyan4973)
• Fix: Sequence Compression API (#3023, #3040, @Cyan4973)
• Fix: Leaking thread handles on Windows (#3147, @animalize)
• Fix: Timing issues with cmake/meson builds (#3166, #3167, #3170, @Cyan4973)

​

Build

• Enhancement: Allow user to select legacy level for cmake (#3050, @shadchin)
• Enhancement: Enable legacy support by default in cmake (#3079, @niamster)
• Enhancement: Meson build script improvements (#3039, #3120, #3122, #3327, #3357, @eli-schwartz and #3276, @neheb)
• Enhancement: Add aarch64 to supported architectures for zstd_trace (#3054, @ooosssososos)
• Enhancement: Support AIX architecture (#3219, @qiongsiwu)
• Fix: ZSTD_LIB_MINIFY build macro, which now reduces static library size by half (#3366, @terrelln)
• Fix: Windows issues with Multithreading translation layer (#3364, #3380, @yoniko) and ARM64 target (#3320, @cwoffenden)
• Fix: cmake script (#3382, #3392, @terrelln and #3252 @Tachi107 and #3167 @Cyan4973)

​

Documentation

• Enhancement: Updated man page, providing more details for --train mode (#3112, @Cyan4973)
• New: Decompressor errata document (#3092, @terrelln)

​

Miscellaneous

• Enhancement: Enable Intel CET (#2992, #2994, @hjl-tools)
• Fix: contrib/ seekable format (#3058, @yhoogstrate and #3346, @daniellerozenblit)
• Enhancement: Improve speed of the one-file library generator (#3241, @wahern and #3005, @cwoffenden)

​

Older Versions

For a complete history of all versions, please see the CHANGELOG file in the repository.