# Cylc: Quick Installation Guide
**See [The Cylc User Guide](https://cylc.github.io/documentation.html) for
more detailed information.** Cylc documentation is now maintained in the
cylc/cylc-doc repository on GitHub.
Cylc must be installed on suite and task job hosts. Third-party dependencies
(below) are not required on job hosts.
### Python 2 or Python 3 ?
Currently in the source code repository:
- **master branch:** Python 3, ZeroMQ network layer, **no GUI** - Cylc-8 Work In Progress
- **7.8.x branch:** Python 2, Cherrypy network layer, PyGTK GUI - Cylc-7 Maintenance
The first official Cylc-8 release (with a new web UI) is not expected until late 2019.
Until then we recommend the latest cylc-7.8 release for production use.
See INSTALL.md in the 7.8.x repository branch, or in your unpacked 7.8.x
release, for how to install Cylc 7. You can download the latest cylc-7 release
tarball from [Cylc Releases](https://github.com/cylc/cylc-flow/releases).