Release Notes

Release Notes#

This document lists major changes across releases.

Added in version 1.1.1: (February 2026)

Added in version 1.1: (February 2026)

Much enhanced protocol fuzzing:
- Protocol fuzzing is now out of beta.
- fandango talk now keeps on producing diverse interactions, systematically covering states and messages until stopped or 100% coverage is reached.
- Detailed documentation with FTP and DNS case studies.
- fandango convert can now produce state diagrams from grammars.
You can now download the documentation as a PDF from the upper-right download icon.
Lots of minor bug fixes.
[development] Major internal refactorings and code quality improvements.
[development] Added support for the uv package manager, including appropriate lock files to ensure compatible and fixed dependency versions

Added in version 1.0: (June 2025)

New command fandango talk for checking outputs and testing protocols (beta).
Much faster parser for .fan files, using C++ code.
Support for regular expressions for producing and parsing.
Support for soft constraints and optimization (maximizing / minimizing).
Using */** expressions for Python-style quantifiers is now operational.
f-strings in Python code are now supported.
Support for libfuzzer harnesses.
New command fandango convert for converting ANTLR and other input specifications.
New command fandango clear-cache for clearing the parser cache.
Improved bit parser.
Lots of minor and major improvements and bug fixes across the board.

Changed in version 1.0:

We now apply Python end-of-line rules to grammar parsing. End continuation lines with \ or use parentheses.
Fuzzing by default is now “infinite”, producing results until stopped. Specify -n N to obtain N outputs.

Added in version 0.8: (April 2025)