*Make sure you view this [upgrade guide from the `master` branch](https://gitlab.com/gitlab-org/gitlab-ce/tree/master/doc/update/6.0-to-6.1.md) for the most up to date instructions.*
GitLab 6.1 is affected by critical security vulnerabilities CVE-2013-4490 and CVE-2013-4489.
**In 6.1 we remove a lot of deprecated code.**
**You should update to 6.0 before installing 6.1 so all the necessary conversions are run.**
## Deprecations
### Global issue numbers
In 6.1 issue numbers are project specific. This means all issues are renumbered and get a new number in their URL. If you use an old issue number URL and the issue number does not exist yet you are redirected to the new one. This conversion does not trigger if the old number already exists for this project, this is unlikely but will happen with old issues and large projects.
## 0. Backup
It's useful to make a backup just in case things go south (with MySQL, this may require granting "LOCK TABLES" privileges to the GitLab user on the database version):
- Make `/home/git/gitlab/config/gitlab.yml` same as <https://gitlab.com/gitlab-org/gitlab-ce/blob/6-1-stable/config/gitlab.yml.example> but with your settings.
- Make `/home/git/gitlab/config/unicorn.rb` same as <https://gitlab.com/gitlab-org/gitlab-ce/blob/6-1-stable/config/unicorn.rb.example> but with your settings.