Versions¶

What this documentation follows¶

These pages document the default branch of each repository, which is the current line of development.

Repository	Documented branch	Latest release
frost	`dev`	v1.0.0 (7 October 2025)
machine-data-model	`dev`	v1.0.0
frost-planner	`main`	v0.2.4

Where the released version behaves differently from what is documented, the page says so.

Frost renamed its components after v1.0.0¶

This is the difference that matters most, because it changes the name of everything you write.

Frost v1.0.0 — the main branch — had six components. The dev branch reorganised them into a cleaner hierarchy, splitting the data model out as a port-less mixin so that the two concrete components can combine it with the communication interface independently.

v1.0.0 (`main`)	Current (`dev`)	What changed
`FrostBase`	`FrostBase`	Unchanged in role.
`FrostInterface`	`FrostInterface`	No longer performs bus registration; that moved to `FrostReactor`. Now splits incoming messages onto four logical actions.
`MessageFilter`	`MessageFilter`	Unchanged in role.
`FrostDataModel`	`FrostNode`	Renamed, and turned into a mixin with no ports of its own.
`FrostMachine`	`FrostReactor`	Merged. v1.0.0 had a separate `FrostReactor` for communication only and `FrostMachine` for communication plus a data model; there is now one component.
`FrostReactor`	(merged into `FrostReactor`)	—
`FrostBus`	`FrostLink`	Renamed. Its data model paths changed from `FrostBus/#Machines` and `FrostBus/MachineInfo` to `FrostLink/#Nodes` and `FrostLink/NodeInfo`.

Other differences on dev:

Registration is symmetric. v1.0.0 had components send a registration request to the bus and retry on a timeout. Components now broadcast to the marker "__target__" on every output port, and record peers both from replies to their own broadcast and from broadcasts they receive — so direct point-to-point wiring works without a router.
A default route by name. Messages for unknown targets are sent to a peer named frost_link.
New subsystems. dev adds FrostScheduler (job-shop scheduling driven by frost-planner) and a simulation package with an Orchestrator, SimModel and an FMI/FMU wrapper, FrostFmu. None of these existed in v1.0.0.

Which one should I use?¶

dev. It is Frost's default branch, it is what its CI tests on every push, and it is what the current applications — xppu-frost, ice-frost — are built against.

Use main only if you have an existing project pinned to v1.0.0. Note that frost-playground is such a project: its submodule tracks main, so its examples will not compile against dev unchanged.

machine-data-model¶

v1.0.0 is the latest release. These pages document dev, which is the default branch.

The library is not on PyPI. Install it from source, or let Frost's requirements.txt pull it in — which is how Frost gets it:

git+https://github.com/glacier-project/machine-data-model.git@dev

Note the @dev: Frost depends on the development branch, not on the release.

MQTT connector support is recent, merged in June 2026. If you are working from an older checkout, only the OPC UA connector will be present.

Toolchain¶

	Version
Python (Frost)	3.12 or later — CI tests 3.12 and 3.13
Python (machine-data-model)	3.11 or later
Java	17, for the Lingua Franca compiler
Lingua Franca	installed via `curl -Ls https://install.lf-lang.org \\| bash -s cli`

Checking for yourself¶

The authoritative answer is always the repository. Two commands settle most questions:

# What is the default branch, and what has been released?
gh repo view glacier-project/frost --json defaultBranchRef,latestRelease

# Which components exist on the branch I am using?
gh api "repos/glacier-project/frost/contents/src/lib?ref=dev" --jq '.[].name'