The Unity documentation is the Unity User Manual and Unity Scripting API Reference.
As we continually improve Unity (that is; the Editor and the engine), we add new features, improve existing features, and sometimes remove old features.
With each Unity release, the Unity documentation changes to reflect this, so make sure you use the correct version of the User Manual and Scripting API Reference to match the version of Unity you’re using.
The version of the documentation which accompanies the current full release of Unity is always available online at docs.unity3d.com.
As well as using the online documentation, you can install it locally on your computer when you install the Unity software. Prior to Unity 5.3, the documentation was always installed along with the software. From version 5.3 onwards, you can choose whether to install the documentation locally via the Unity Download Assistant.
We republish the online documentation for the current full release version of Unity regularly with corrections and missing content regularly. (You can see the publish version of the documentation at the bottom of every page.)
If there is a current Unity beta release, we also update the current public beta release documentation with corrections, missing content, and feature updates regularly.
However, note that we do not update and re-publish:
the installer (offline) documentation.
legacy documentation, that is; documentation for Unity versions which are no longer a current beta or full release of Unity.
If you need the latest publish of the documentation offline, you can download it outside of the installer. See the Offline Documentation page for details.
Most people use the latest full release version of Unity and so use the documentation at docs.unity3d.com.
Some people need to use older versions of Unity. This might be the case for you if you are maintaining or in long-term development of a project which uses an older version of Unity.
If you are using an older version of Unity, the installer (offline) documentation matches that version of Unity. However if you chose not to install local documentation, or want to ensure you can access the latest publish of the documentation, you can access older versions of the Unity documentation online. (See list below.)
Documentation for Unity versions which are no longer the current full release or beta release version of Unity.
This documentation is frozen - we do not correct, update or republish it. However Long-term support versions may be supported for a longer time.