---
title: Versions
description: The five version axes a client meets — platform build, agent capability version, API contract, portal build and pipeline versions — where each is exposed, how to detect a change, and the compatibility rules.
locale: en
version: 0.2.0
canonical: https://enterium-developer-docs.pages.dev/developers/reference/versions/
---

> Documentation index: https://enterium-developer-docs.pages.dev/developers/llms.txt — every page of this portal has a Markdown twin at <route>.md; the frozen API contract is at https://enterium-developer-docs.pages.dev/developers/api/openapi.json.

Five things carry a version, on purpose independently: bumping one does not
imply the others changed. This page says where to read each and what a change
means for you.

## The axes

| Axis | Where you read it | Scheme | Changes when |
| --- | --- | --- | --- |
| **Platform build** | `version` in `GET /healthz` and `/api/status.json` | SemVer, derived from the release history | Any module ships — most builds do not touch what an agent can do |
| **Agent capability version** | `x-capability-version` header on every API response · `serverInfo.version` on MCP connect · `capability_version` in `start_here` | Date-anchored, monotonic (`2026-09-03.1`) — a plain string compare works | The **agent-facing read surface** changes: new/changed tools, fields, semantics. Every bump has an entry in the [capability changelog](../release-notes/#agent-capability-changelog) |
| **API contract** | `info.version` in [`openapi.json`](/developers/api/openapi.json) (frozen with this portal build) | SemVer | Paths, schemas or declared responses change |
| **Portal build** | [`versions.json`](/developers/versions.json) (`version`, `builtAt`) · [`manifest.json`](/developers/manifest.json) (route → content hash) · the badge under every page title | SemVer | The documentation is republished |
| **Pipeline versions** | The [pipeline catalog](../../pipelines/catalog/) | Per pipeline, immutable directories | A pipeline is carved — see [Version lifecycle](../../pipelines/versioning/) |

## Detecting change

- **Agents:** cache `capability_version`; on every reconnect pass it to `start_here`
  as `last_seen_version` — `changed: true` plus `whats_new` is your diff. Between
  connects, the `x-capability-version` header on any response tells you the same
  without a call.
- **Docs consumers:** compare the stored `manifest.json` against the current one and
  re-read only the routes whose hash moved; `.md` twins carry an `ETag`.
- **Everyone:** [`changelog.json`](/developers/changelog.json) (JSON Feed 1.1) is the machine
  twin of the [release notes](../release-notes/) — subscribe to it.

## Compatibility rules

1. **Additive is silent.** New endpoints, new tools and new optional fields
   appear without a contract major bump; ignore fields you do not know.
2. **Renames and removals are announced first.** They enter the capability
   changelog under `deprecated` with the replacement, live side by side for at
   least one capability version, then move to `removed` in the release notes.
3. **Breaking contract changes bump the contract's major** and the capability
   version on the same day; the frozen `openapi.json` of the previous portal
   build stays available in the release history.
4. **Pipeline versions never mutate.** A change is a new version directory; the
   catalog pin decides which one production runs.