Supported REST API versions

You can determine which versions of an API call are available for a specific deployment of the Fabric Services System by performing an unauthenticated HTTP GET request to the https://fss.domain.tld/rest/about/version URI:

# curl -s https://fss.domain.tld/rest/about/version | jq
{
  "fss": {
    "gitCommit": "v22.4.1-1462"
  },
  "fss-alarmmgr": {
    "gitCommit": "v22.4.1-1462-gca271333",
    "builtDate": "2022-03-23T05:24:14+00:00",
    "gitBranch": "22_4_1",
    "appName": "fss-alarmmgr",
    "apiVersions": [
      {
        "version": "v1",
        "status": "CURRENT",
        "baseURL": "fss.domain.tld/rest",
        "swaggerDoc": "fss.domain.tld/rest/alarmmgr/v1/docs/swagger.yaml"
      }
    ]
  },
  "fss-auth": {
    "gitCommit": "v22.4.1-1462-gca271333",
    "builtDate": "2022-03-23T05:15:55+00:00",
    "gitBranch": "22_4_1",
    "appName": "fss-auth",
    "apiVersions": [
      {
        "version": "v1",
        "status": "CURRENT",
        "baseURL": "fss.domain.tld/rest",
        "swaggerDoc": "fss.domain.tld/rest/auth/v1/docs/swagger.yaml"
      }
    ]
  },
...

All services and components of the Fabric Services System display in the resulting list. Only those that have an apiVersions attribute actually provide an API service.

API version strategy and backward compatibility

The Fabric Services System is composed of multiple individual applications or services. Each of these services has its own API with its own API version. While most of the services have the same API version as their latest, it is important to keep track of API version changes.

For each service at least two versions are always available, unless a service is using version 1 for its API. The older version is available for customers upgrading from an older version to ensure that their scripts, tools, and integrations can continue functioning on the old API after the upgrade and before they are updated to the new API.

As soon as a new API version is introduced for that service, all new functionality for the service is available only on the new API version. The older API version can only be used for the older functionality.

The platform also guarantees backward compatibility within the same version of the API. This strategy allows for the creation of scripts, tools and integrations using the same API version across multiple releases, without having to adapt them every time the platform is upgraded.
Note: Between versions of the API, backward compatibility can sometimes break when there is a need for significant changes. When upgrading the scripts, tools, and integration to use the new API, investigate and understand the impact of these changes and act accordingly.