# Changelog and deprecation

Documentation release notes and the implemented research-version retirement policy.

## This documentation release
Adds task guides, an OpenAPI-generated reference, agent setup, Markdown mirrors, search and documentation-scoped light/dark themes. It documents the change feed (/api/changes and mode=changes), document observations and revision hashes, maintained watch= topics and the Team contact tier as the API serves them; the dated API record is the [API changelog](/data/api-changelog.json).

## Deprecation policy
The research implementation identifies the current transport as v2. Its internal v1 preview was replaced in place. A future v3 is intended to coexist with v2 during a notice period; Deprecation and Sunset headers will announce retirement. The published policy (info.x-deprecation-policy in [OpenAPI](/openapi.json)) gives at least 180 days' notice before a published operation, parameter, field or error code is removed or changed incompatibly.

## Check before upgrading
Read the operation's contract and live headers. Editorial topic versions, collector schema_version and research API version describe different objects. [Schema versioning](/docs/data/schema-versioning) explains the distinctions.