Long-term support


Long-term support is a product lifecycle management policy in which a stable release of computer software is maintained for a longer period of time than the standard edition. The term is typically reserved for open-source software, where it describes a software edition that is supported for months or years longer than the software's standard edition.
Short term support is a term that distinguishes the support policy for the software's standard edition. STS software has a comparatively short life cycle, and may be afforded new features that are omitted from the LTS edition to avoid potentially compromising the stability or compatibility of the LTS release.

Characteristics

LTS applies the tenets of reliability engineering to the software development process and software release life cycle. Long-term support extends the period of software maintenance; it also alters the type and frequency of software updates to reduce the risk, expense, and disruption of software deployment, while promoting the dependability of the software. It does not necessarily imply technical support.
At the beginning of a long-term support period, the software developers impose a feature freeze: They make patches to correct software bugs and vulnerabilities, but do not introduce new features that may cause regression. The software maintainer either distributes patches individually, or packages them in maintenance releases, point releases, or service packs. At the conclusion of the support period, the product either reaches end-of-life, or receives a reduced level of support for a period of time.

Rationale

Before upgrading software, a decision-maker might consider the risk and cost of the upgrade.
As software developers add new features and fix software bugs, they can accidentally introduce new bugs or break old functionality. When such a flaw occurs in software, it is called a regression. Two ways that a software publisher or maintainer can reduce the risk of regression are to release major updates less frequently, and to allow users to test an alternate, updated version of the software. LTS software applies these two risk-reduction strategies. The LTS edition of the software is published in parallel with the STS edition. Since major updates to the STS edition are published more frequently, it offers LTS users a preview of changes that might be incorporated into the LTS edition when those changes are judged to be of sufficient quality.
While using older versions of software may avoid the risks associated with upgrading, it may introduce the risk of losing support for the old software. Long-term support addresses this by assuring users and administrators that the software will be maintained for a specific period of time, and that updates selected for publication will carry a significantly reduced risk of regression. The maintainers of LTS software only publish updates that either have low IT risk or that reduce IT risk. Patches for LTS software are published with the understanding that installing them is less risky than not installing them.

Software with separate LTS versions

This table only lists those have a specific LTS version in addition to a normal release cycle. Many projects, such as CentOS, provide a long period of support for every release.
SoftwareSoftware typeDate of first LTS releaseLTS periodSTS periodNotes
DjangoApplication framework
3 years16 months
Debian GNU/LinuxLinux distribution1 June 20142 years3 yearsA total support period is 5 years.
FirefoxWeb browser
1 year6 weeksMozilla's LTS term is "Extended Support Release" .
Joomla!CMS
2 years, 3 months7 monthsSince Joomla! is a web application, long-term support also implies support for legacy web browsers.
LaravelApplication framework
3 years1 yearFor LTS releases, bug fixes are provided for 2 years and security fixes are provided for 3 years. For general releases, bug fixes are provided for 6 months and security fixes are provided for 1 year.
Linux kernelKernel
, 6, 10+ yearsLinux kernel v2.6.16 and v2.6.27, were unofficially supported in LTS fashion before a 2011 working group in the Linux Foundation started a formal Long Term Support Initiative. The LTS support period was upped to 6 years; Linux kernel 4.4 will have 6 years of support before being taken over by the "Civil Infrastructure Platform" project that plans to maintain it for a minimum of 10 years under "SLTS ". "The use cases CIP project is targeting have a life cycle of between 25 and 50 years." and the CIP envisiones 15+ years of support.
Linux MintLinux distribution5 years6 monthsAt version 13 the LTS period increased from three years to five, since Linux Mint derives from Ubuntu.
JavaVirtual machine and runtime environment
4 years6 monthsAll versions prior to Java 9 were supported for long periods of time.
MoodleApplication framework12 May 2014 3 years18 months
MatomoWeb analytics
≥12 months~4 weeks
Node.jsRuntime system
18 months12 months
SymfonyApplication framework3 years8 months
Tiki-wikiWiki/CMSMay 2009 5 years6 monthsEvery third version is a Long Term Support version.
Trisquel 7.0Linux distribution2014-11-045 years1 yearLinux Kernel-libre 3.13, GNOME fallback 3.12 and Abrowser or GNU IceCat
TYPO3CMS
3 years TYPO3 is a web application stewarded by the TYPO3 Association.
UbuntuLinux distribution
5 years9 monthsA new LTS version is released every two years. From 2006 through 2011, LTS support for the desktop was for approximately two years, and for servers five, but LTS versions are now supported for five years for both.
Windows 10Operating system
10 years18 months The Long-Term Servicing Channel releases of Windows 10 are supported for 10 years for mission critical machines. The LTSC release gets monthly security updates; the updates to the LTSC release bring little to no feature changes. Every 2-3 years, a new major LTSC release is published, but businesses may opt to stay on their current LTSC version until its end-of-life. The LTSC release is available only for businesses running the Windows 10 Enterprise edition. Regular consumers on the Semi-Annual Channel get new versions of the operating system approximately every six months while business customers get upgraded to new versions of SAC approximately four months after Microsoft released the SAC release for regular consumers.