The latest Internet-Drafts at the IETF are the draft-handrews-json-schema*-00 documents, which correspond to the draft-07 meta-schemas. These were published on 2017-11-19. (Due to a change in author/editorship the I-D numbering was reset to -00 again).

Please see the release notes for more information on this release and on migrating from draft-06 or draft-04.

The specification is split into three parts, Core, Validation, and Hyper-Schema, along with a related specification, Relative JSON Pointers:

JSON Schema Core defines the basic foundation of JSON Schema
JSON Schema Validation defines the validation keywords of JSON Schema
JSON Hyper-Schema (errata) defines the hyper-media keywords of JSON Schema
Relative JSON Pointers extends the JSON Pointer sytnax for relative pointers

They are also available on the IETF main site:

Meta-schemas

The meta-schemas are schemas against which other schemas can be validated. They are self-descriptive: the JSON Schema meta-schema validates itself, while the JSON Hyper-Schema meta-schema both validates itself and defines its own “self” link. The latest meta-schema is draft-07.

Core/Validation meta-schema Used for schemas written for pure validation.
Hyper meta-schema Used for schemas written for validation and hyper-linking.

If you are accessing the above meta-schema links from a web browser, you will need to save the file then open it as a JSON document.

Migrating from draft-04 or draft-06

The release notes discuss the changes impacting users and implementors:

Older drafts

Please see Specification Links for older drafts and the latest unreleased version of the specification.