Lingua Franca 0.13.0

v0.13.0 (2026-08-16)

** Highlights **

This release adds a number of major features, mostly concerning federated programs:

• Security: You can now encrypt communication between federates using TLS (Transport Layer Security), a public-key encryption technology that is standard on the internet. You can also specify to use SST (Secure Swarm Toolkit), A decentralized authorization and communication security framework using the iotauth platform. See the Security page of the handbook.

• Package System: You can create and use packages of reusable reactors more simply without using lingo. An evolving set of standard packages is in progress. See the Importing Packages page of the handbook.

• Transient Federates: Federated programs in the C and Python targets can have transient federates, which need not be present when the federation starts up and can come and go during the execution of the federation. See the Transient Federates page of the handbook.

• Polyglot Federations: A new Polyglot target supports creating federations where some federates use the C target and some use the Python target. See See the Polyglot Federations page of the handbook.

• Protobuf Serialization: Communication between federates can now use Protocol Buffers, Google's data interchange format, also known as protobufs.

• Control over Start Time: You can now specify on the command line that the start time of a program should be a multiple of a time value. Use the --start-time-multiple <num> <units> or -m <num> <units> command-line arguments.

🚀 New Features

• Support Protobufs serialization and deserialization in the C and CCpp targets #2628 (@edwardalee)
• Implement protobuf serialization between LF federates in Python runtime and add a test #2632 (@hokeun)
• Apply pluggable security (TLS, SST) for federated execution #2466 (@Jakio815)
• Implement Polyglot target supporting a mixture of C and Python targets. #2635 (@hokeun)
• Add --start-time-multiple (-m) command-line option #2641 (@edwardalee)
• Simpler package system based on git clones. #2654 (@edwardalee)
• Add support of transient federates in C and Python targets for centralized and decentralized coordination. #2213 (@ChadliaJerad)

✨ Enhancements

• Import top-level preamble of all imported files #2620 (@edwardalee)
• Support Protobufs serialization and deserialization in the C and CCpp targets #2628 (@edwardalee)
• Expose lf.set_fed_maxwait and lf.get_fed_maxwait in the Python target #2631 (@edwardalee)
• Add support for extends keyword in rust target #2630 (@Eggsrael)
• Update validator to acknowledge that micro-LF supports multiports #2639 (@edwardalee)
• Show absent_after in diagrams if explicitly given by the programmer #2640 (@edwardalee)
• Support changing Rust Editions in Rust target #2637 (@Eggsrael)
• Add endpoint option to trace-plugin target property #2589 (@lsk567)
• Add support for Docker in the Rust target #2648 (@Eggsrael)
• Support the .ulf file extension for micro-LF programs #2646 (@edwardalee)
• Make target declaration optional for .ulf files #2653 (@edwardalee)
• Simpler package system based on git clones. #2654 (@edwardalee)
• Support .ulf extension for package imports #2668 (@edwardalee)
• Support numbers in import package names #2677 (@edwardalee)

🔧 Fixes

• Fix Python target on macOS with statically-linked Python (e.g., conda) #2623 (@depetrol)
• Exclude FEDERATED_SST from runWithThreadingOff and runAsFederated tests #2636 (@Jakio815)
• Add startup delay for local SST Auth server #2638 (@Jakio815)
• Make default maxwait forever #2629 (@edwardalee)
• Raising error for unsupported decentralized coordination for TypeScript target. #2642 (@hokeun)
• Fix connection bug with port to multiport bank broadcast #2645 (@edwardalee)
• Fix named reactions compile error in the Python target #2673 (@edwardalee)
• Fixed federate self loops. #2674 (@edwardalee)
• Fix ZDC hang with upstream physical action #2675 (@edwardalee)

🧪 Tests

• Deflake test by using default maxwait #2643 (@edwardalee)

• Remove the deprecated pnpm block and replace with new file #2624 (@edwardalee)

Submodule lf-lang/reactor-c

🚀 New Features

• Apply pluggable security (TLS, SST) for federated execution. #515 (@Jakio815)
• Add --start-time-multiple (-m) command-line option. #585 (@edwardalee)
• Add support for transient federates for centralized and decentralized coordination. #358 (@ChadliaJerad)

✨ Enhancements

• Expose lf.set_fed_maxwait and lf.get_fed_maxwait functions in the Python target #584 (@edwardalee)

🔧 Fixes

• Change maxwait default to forever. #583 (@edwardalee)
• Update sst-c-api's default branch from master to main. #586 (@Jakio815)
• Fix ZDC hang with upstream physical action #593 (@edwardalee)

🚧 Maintenance and Refactoring

• Improve socket messages and add a needed mutex #587 (@edwardalee)

Submodule lf-lang/reactor-cpp

• No Changes

Submodule lf-lang/reactor-rs

• No Changes