3.0.0 — Pure Python Rewrite

python-snap7 3.0.0 — Pure Python Rewrite

This is a major release that completely rewrites python-snap7 as a pure Python S7 communication library. The C snap7 shared library is no longer used — the entire protocol stack (TPKT, COTP, and S7) is now implemented in pure Python.

The name "python-snap7" is historical — the library originally started as a Python wrapper around the Snap7 C library. As of this release, the C library is no longer needed, but the name is kept for backwards compatibility.

What's new

• Pure Python implementation — no native dependencies, no shared libraries
• Works everywhere — any platform that runs Python 3.10+, including ARM, Alpine Linux, and other environments where the C library was difficult or impossible to install
• Easier to extend — new features and protocol support can be added directly in Python
• Complete TPKT (RFC 1006) and COTP (ISO 8073) transport layer implementation
• Native S7 protocol PDU encoding/decoding
• Pure Python server implementation for testing and simulation
• Full type annotations with mypy strict mode
• CLI interface for running an S7 server emulator (pip install "python-snap7[cli]")

Breaking changes

This release completely breaks with the previous approach of wrapping the C snap7 shared library. While the public API is largely the same, this is a fundamental change under the hood. If you experience issues:

1. Please report them on the issue tracker with a clear description and the version you are using (python -c "import snap7; print(snap7.__version__)")
2. As a workaround, pin to the last pre-3.0 release: pip install "python-snap7<3"

Thanks

Special thanks to the following people for testing, reporting issues, and providing feedback during the 3.0 development:

• @lupaulus — extensive testing and bug reports
• @spreeker — testing and feedback
• @nikteliy — review and feedback on the rewrite
• @amorelettronico — testing
• @razour08 — testing
• @core-engineering — bug reports
• @AndreasScharf — bug reports
• @Robatronic — bug reports
• @hirotasoshu — feedback
• @PoitrasJ — bug reports

2.1.1

Fix Read the Docs build configuration for pre-3.0 documentation.

• Fix .readthedocs.yaml to install from pyproject.toml extras instead of missing requirements-dev.txt
• Add mock imports in doc/conf.py so autodoc works without the native snap7 C library on RTD
• Use sphinx_rtd_theme for consistent styling

v2.1.0

What's Changed

Bug Fixes

• Fix PLC setter functions for memoryview compatibility (#575)
• Cache error_text() instead of check_error() (#552)

Improvements

• Add ASCII validation in set_string() with isascii() (#561)
• Update read_multi.py example (#563)
• Code quality improvements and comprehensive documentation (#568)
• Fix typo: ussage -> usage (#564)

CI/CD & Infrastructure

• Modernize CI/CD: switch to uv, fix Python 3.11+ compatibility (#576)
• Drop Ubuntu 20.04 from CI matrix (#562)

Supported Python versions

• Python 3.10, 3.11, 3.12, 3.13, 3.14

Full Changelog: 2.0.2...2.1.0

2.0.2

What's Changed

• we dont need enum_tools.autoenum by @gijzelaerr in #548

Full Changelog: 2.0.1...2.0.2

2.0.1

What's Changed

• better parsing to avoid bugs when variables name contain whitespaces by @Novecento99 in #529
• update docstring to match new API #537 by @gijzelaerr in #538
• fix indentation of docs by @gijzelaerr in #544
• make test timezone aware by @gijzelaerr in #543

New Contributors

• @Novecento99 made their first contribution in #529

Full Changelog: 2.0.0...2.0.1

2.0.0

major release with backwards compatibility changes

This release is a restructure of the codebase, cleaning up old inconsistencies and spelling mistakes. Although attempts were made to keep the API backwards compatible, a method argument might have changed here and there. This release is also 100% typed, helping us find and fix tiny bugs and mistakes.

This makes the python-snap7 'done', all functionality is implemented and no changes in the API are expected anymore.

Most important changes

• Improve typing by @nikteliy in #516
• Improve use of enum types by @gijzelaerr in #515

Full Changelog: 1.4.1...2.0.0

1.4.1

What's Changed

• update container workflow by @gijzelaerr in #509
• avoid creating compressed tags set by @nikteliy in #510
• Make client and server a contextmanager by @gijzelaerr #512
• Drop Python 3.8 from metadata and doc by @gijzelaerr #513
• Drop Snap7Library singleton and use python functools caching by @gijzelaerr #514
• Doc: Typo and samples for CPU State and CP State @lupaulus #508

Full Changelog: 1.4...1.4.1

1.4

What's Changed

• Fix #431 by @nikteliy in #432
• Add arm32v7 wheel (Issue #376) by @nikteliy in #442
• Update github actions by @nikteliy in #443
• Fix utils by @nikteliy in #444
• Add reusable action by @nikteliy in #446
• append arm in installation doc by @Tathar in #450
• Fix example by @FiloCara in #452
• Fix #451 by @nikteliy in #453
• Add pre-commit by @nikteliy in #460
• add missing lreal to util.py by @spreeker in #487
• Prepare for 1.4 by @gijzelaerr in #477
• Issue 474 fix by @nikteliy in #501
• try to fix more builds by @gijzelaerr in #502
• Also include submodules by @gijzelaerr in #503
• fix build by @nikteliy in #504
• use venv everywhere by @gijzelaerr in #505
• fix bad cli_as_callback implementation by @gijzelaerr in #506
• add python 3.12 wheels, drop 3.8 and older by @gijzelaerr in #474

New Contributors

• @kaisersource made their first contribution in #425
• @Tathar made their first contribution in #450
• @FiloCara made their first contribution in #452

Full Changelog: 1.3...1.4

1.3

What's Changed

• drop python 3.6 versions in checks by @swamper123 in #369
• fix set_string by @swamper123 in #368
• use https for links by @imba-tjd in #370
• use more pythonic syntax by @imba-tjd in #373
• fixed DB class not allowing to write BYTE values to rows by @vmsh0 in #377
• Deprecate old osx by @gijzelaerr in #383
• Add support to read/write space-padded fixed-length strings by @vmsh0 in #378
• DB usability improvements by @vmsh0 in #385
• Make all internal imports relative by @vmsh0 in #386
• fixed typo in portnumber by @Cube707 in #408
• fix linux build by @gijzelaerr in #410
• implement __main__.py enty points by @Cube707 in #409

New Contributors

• @imba-tjd made their first contribution in #370
• @vmsh0 made their first contribution in #377
• @Cube707 made their first contribution in #408

Full Changelog: 1.2...1.3

1.2

What's Changed

• fix wheel tag for linux x86_64 by @nikteliy in #297
• Fixed typo area doesn't exist areas does by @Ofloo in #306
• add get_time and set_time in util by @Yingliangzhe in #308
• modification of TIME data type by @Yingliangzhe in #311
• added DATE_AND_TIME Value as Datetime object by @zsisamci in #312
• #273 by @nikteliy in #321
• Add byte type parsing to DB_Row API + set parsing case insensitive by @LoicGRENON in #315
• added missing types in WordLen by @zsisamci in #326
• Add support for read/write unsigned value from bytearray by @LoicGRENON in #316
• fixing ip string paramters to c function by @zsisamci in #329
• Add py.typed marker file by @mthuurne in #342
• require correct package name, fixes issue #344 by @gijzelaerr in #345
• Fix warnings by @nikteliy in #350
• Update license identifier by @Shortfinga in #349
• Update client db_write docs by @pwablito in #352
• Fix db_offset calculation error by @lubbbert in #351
• fix #355 by @swamper123 in #359
• fix #272 by @swamper123 in #360
• fix get_time for small values by @swamper123 in #358
• add more getter methods for utils by @swamper123 in #357
• Prepare for 1.2 by @gijzelaerr in #364

New Contributors

• @Ofloo made their first contribution in #306
• @zsisamci made their first contribution in #312
• @LoicGRENON made their first contribution in #315
• @mthuurne made their first contribution in #342
• @Shortfinga made their first contribution in #349
• @pwablito made their first contribution in #352
• @lubbbert made their first contribution in #351

Full Changelog: 1.1...1.2