#pragma section-numbers 2
= Feature Levels =
How we categorize features.

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== Strata ==
Mercurial tries to avoid having every user become experts in version control, so it tries to organize functionality into different strata:

 * basic commands (the <20 commands shown by just typing 'hg')
  * the commands every user should know to get work done
 * core features
  * common features available to all users
  * safe for inexperienced users
  * comparable to the core features present in most systems
  * covered by our [[CompatibilityRules|backwards-compatibility rules]]
 * [[UsingExtensions#Extensions_bundled_with_Mercurial|bundled extensions]]
  * same level of testing and support as core features
  * also covered by our backwards-compatibility rules
  * not essential functionality
  * not appropriate for all users
  * some may be dangerous (e.g. strip)
 * third-party extensions
  * not written/tested/supported/maintained by us
  * may break backwards compatibility
  * may violate core UI expectations
  * may need upgrading when you upgrade Mercurial

== Life cycle ==
We also have varying levels of feature support, corresponding to different stages in a feature's lifecycle:

 * experimental/undocumented
  * not intended for production use
  * feature is subject to change or removal
  * support not guaranteed
 * production
  * fully supported, actively developed
  * fully maintained and tested for backwards compatibility
 * [[FeaturesOfLastResort|feature of last resort]]
  * don't use this feature in production unless you really need to
  * still supported and developed
  * still maintained and tested for backwards compatibility
 * [[UnlovedFeatures|unloved]]
  * users are strongly discouraged from using this feature
  * not a support or development priority
  * still maintained and tested for backwards compatibility
 * deprecated
  * removed from documentation
  * only regressions will get support attention
  * still maintained and tested for backwards compatibility
  * '''not''' scheduled for removal
 * removed
  * only used for features that can be removed without negative impact
  * very rare

== See also ==

 * UpgradingMercurial
 * UpgradeNotes

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