# Getting and installing &debian;

The official document giving installation instructions is the Debian GNU/Linux Installation Guide. We'll give some additional notes about getting and installing &debian; here.

## What is the latest version of Debian?

Currently there are three versions of &debian;:

release &release;, a.k.a. the "stable" distribution or &releasename;

- This is stable and well tested software, it changes if major security or usability fixes are incorporated.

the "testing" distribution, currently called &nextreleasename;

- This is where packages that will be released as the next "stable" are placed; they've had some testing in unstable but they may not be completely fit for release yet. This distribution is updated more often than "stable", but not more often than "unstable".

the "unstable" distribution

- This is the version currently under development; it is updated continuously. You can retrieve packages from the "unstable" archive on any Debian mirror site and use them to upgrade your system at any time, but you may not expect the system to be as usable or as stable as before - that's why it's called "unstable"!

Please see dists for more information.

## Are there package upgrades in "stable"?

Generally speaking, no new functionality is added to the stable release. Once a Debian version is released and tagged "stable" most packages will only get security updates. That is, packages for which a security vulnerability has been found after the release will be upgraded. All the security updates are served through security.debian.org.

However, there are some cases in which packages will be updated in stable. For example:

- When an urgent update is required to ensure the software continues working.

- The package is a data package and the data must be updated in a timely manner.

- The package needs to be current to useful to end user (e.g. some security software, such as anti-malware products).

- The software is a leaf package and is broken by changes external to the distribution.

Users that wish to run updated versions of the software in stable have the option to use "backports". Backports are recompiled packages from testing (mostly) and unstable (in a few cases only, e.g. security updates), so they will run without new libraries (wherever it is possible) on a stable Debian distribution. Users can configure their system to use the backports repository and download specific software. However, it is recommended to pick out single backports which fit the specific needs, and not to use all backports available. For more information read the Wiki entry describing sofware available to Debian users and Wiki entry on backports.

Security updates serve one purpose: to supply a fix for a security vulnerability. They are not a method for sneaking additional changes into the stable release without going through normal point release procedure. Consequently, fixes for packages with security issues will not upgrade the software. The Debian Security Team will backport the necessary fixes to the version of the software distributed in "stable" instead.

For more information related to security support please read the Security FAQ or the Debian Security Manual.

## Where/how can I get the Debian installation images?

You can get the installation images by downloading the appropriate files from the Debian website.

Please refer to Debian GNU/Linux on CDs for more information about CD (and DVD) images.

## How do I install Debian from CD-ROMs?

Installing Debian from CD is straightforward: configure your system for booting off a CD, insert your CD, and reboot. Your system will now be running the Debian Installer. See the Debian GNU/Linux Installation Guide for more information.

## Why does the official stable released CD-ROM contain symlinks for "frozen" and "unstable"? I thought this CD contains just "stable"!

Official Debian CD images indeed contain symlinks like:

     /dists/frozen -> &releasename;/
     /dists/stable -> &releasename;/
     /dists/testing -> &releasename;/
     /dists/unstable -> &releasename;/

so that they work when your sources.list has an entry like

     deb cdrom:[<name as on cd label>]/ unstable main [...]

.

The fact these symlinks are present does not mean the image is "unstable" or "testing" or anything. Read the CD label in `/.disk/info` to find out which Debian version it contains. This information is also present in `/README.txt` on the CD.

Read to find out what the current "stable" and "testing" releases are.

## Can I get and install Debian directly from a remote Internet site?

Yes. You can boot the Debian installation system from a set of files you can download from our archive site and its mirrors.

You can download a small CD image file, create a bootable CD from it, install the basic system from it and the rest over the network. For more information please see .

## Are there any alternative strategies for booting the system installer?

Yes. Apart from CD or DVD, you can install &debian; by booting from USB memory stick, directly from hard disk, or using TFTP net booting. For installing on multiple computers it's possible to do fully automatic installations. NB: not all methods are supported by all computer architectures. Once the installer has booted, the rest of the system can be downloaded over the network, or installed from local media. See the Debian GNU/Linux Installation Guide for more information.