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Last modified: 6 November 2019


Platform Support

Python 3.5

CIAO 4.11 is only distributed with Python 3.5. The reason for moving to Python 3 is that the support for Python 2.7 is ending in 2020, and so many of the main scientific packages are also ending support for this version at the same time.

CIAO 4.11 is available as precompiled binaries for the following platforms:


The Linux builds are done on a CentOS 6.9 machine and have been fully tested on CentOS 6 and Fedora 25+. The Linux build will not work on some older Linux operating systems, including CentOS 5 and earlier versions of Fedora. Linux users may need to install the ncurses5 compatibility package using their Linux distribution's package manager.

CIAO 4.11 does not run on standard installations of:

  • Any 32 bit Linux
  • Cent OS5
  • RHEL version 5 or lower
  • Slackware Linux (missing SELinux system library)

This is the default Linux distribution and will be installed automatically on all non-Ubuntu based distributions. The following is a short list of distributions where it will be installed: Fedora, RedHat, CentOS, ScientificLinux, openSUSE, and Mageia.

Linux Ubuntu

The Ubuntu build of CIAO, LinuxU, was built on an Ubuntu 14.04 LTS machine. It will be automatically selected for Ubuntu distributions (14.04LTS, 16.04LTS, 18.04LTS, and the standard releases, such as 18.10) as well as for distributions derived from Ubuntu such as LinuxMint 17 and LinuxMint18.

Windows Subsystem of Linux (WSL)

CIAO is not supported using any Linux distribution running under the Windows Subsystem for Linux (WSL). The CXC has not done any testing with this configuration.

Mac OS X
macOS Catalina

The CXC has done limited testing of CIAO 4.11 on macOS Catalina (10.15) using the binaries compiled on macOS High Sierra (10.13). Thus far there are no reported problems specific to CIAO; however, Apple's increased security protection may cause problems for users trying to install CIAO or other software outside the user's home directory. SAOImageDS9 Darwin|Aqua users will need to install the Catalina version of ds9 v8.1rc1 or later.

There are 3 binary releases for Apple, one for each OSX 10.11 (El Capitan), OSX 10.12 (Sierra), and macOS 10.13 (High Sierra). Users with macOS Mojave should use the version built for macOS High Sierra. CIAO 4.11 does not run on Mac OS X 10.10 and lower, including on 32-bit or PowerPC machines. The table below lists recent CIAO versions and their supported macOS versions:

macOS support in CIAO
CIAO release supported macOS versions
CIAO 4.11 10.11, 10.12, 10.13, 10.14
CIAO 4.10 10.10, 10.11, 10.12
CIAO 4.9 10.9, 10.10, 10.11, 10.12
CIAO 4.8 10.8, 10.9, 10.10, 10.11
CIAO 4.7 10.6, 10.7, 10.8, 10.9

In the table above, 10.6 means OS-X Snow Leopard, 10.7 means OS-X Lion, 10.8 means OS-X Mountain Lion, 10.9 means OS-X Mavericks, 10.10 means OS-X Yosemite, 10.11 means OS-X El Capitan, 10.12 means macOS Sierra, 10.13 means macOS High Sierra, and 10.14 means macOS Mojave (which uses the High Sierra build for CIAO 4.11).

Explanation of Platform Support

The CXC's commitment to support a platform - i.e. a version of an operating system - means that we undertake to fix bugs on that system. This requires that we are able to compile CIAO from source on each platform, which is a much greater commitment than simply providing a compatible binary. Additionally, it is typically necessary to support several versions of each operating system: former, current and new.

When we support a system:

  1. We test every tool on every platform via a large number of regression tests and scripts; this requires a greater amount of time when the number of systems increases.
  2. We have to have current machines running each of these systems.
  3. We make a tarball and install it on each system; this process is never problem-free, and takes manpower and time.

As a result, we are not able to support a larger number of systems than we currently do. We gather information from users on what platforms they are running (or want to use) in order to prevent the overextension of our resources. Please contact the CXC Helpdesk if you have input you would like the CXC to consider for the next release of CIAO.