> For the complete documentation index, see [llms.txt](https://docs.nxcframework.net/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.nxcframework.net/nexus-core-docs/reference/versions.md).

# Versions and support

What a version number means, and what is supported.

## Below 1.0.0, contracts are unstable

A minor version increment **may carry breaking changes**. That is not how semantic versioning usually reads, and it is stated plainly rather than discovered.

Pin exact versions. Install a whole [compatibility set](/nexus-core-docs/reference/compatibility-sets.md).

## Two different numbers

**The version** — `0.4.0` — is that resource's own release number.

**The contract version** — `contract v3` — is the promise other resources depend on. It rises only when the shared surface changes, so a resource can say "I need contract 3 or later" and fail at startup with a sentence naming the cause rather than at whichever line first reached a missing function.

`nxc_versions` prints both.

## What is supported

**The current compatibility set.** One set at a time.

There is no long-term support branch, no backporting, and no security patching of older sets. That is honest for a project at this stage rather than a policy anyone chose — the alternative would be promising maintenance nobody is in a position to provide.

## Reading a changelog

Each resource has one, and each entry says what changed and why. The **Known limitations** section is the one worth reading before an upgrade: it records what does not work, deliberately, so you can tell a limitation from a defect.

## Reporting against a version

Always include `nxc_versions` output. A report against an unknown version usually needs a round trip before anyone can start. See [Getting help](/nexus-core-docs/reference/help.md).


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