Since GitLab 9.0, API V4 is the preferred version to be used.
V3 will remain working until at least GitLab 9.3. The V3 API documentation is still [available](https://gitlab.com/gitlab-org/gitlab-ce/blob/8-16-stable/doc/api/README.md).
API v3 will continue to work until August 2017. In the meantime, we advise you
to make any necessary changes to applications that use the v3 API. The V3 API
documentation is still [available](https://gitlab.com/gitlab-org/gitlab-ce/blob/8-16-stable/doc/api/README.md).