Add a page describing Godot's release policy (#3662)

about/index.rst

@@ -8,6 +8,7 @@ About
    introduction
    faq
    docs_changelog
+   release_policy
 
 .. history
 .. authors

about/release_policy.rst

@@ -0,0 +1,84 @@
+.. _doc_release_policy:
+
+Godot release policy
+====================
+
+Godot versioning
+----------------
+
+Godot uses ``major.minor.patch`` version numbering. However, it does not
+strictly follow `Semantic Versioning <https://semver.org/>`__. This means that
+releases considered "semver-minor" by that standard (such as 3.1 -> 3.2) will
+most likely introduce breaking changes. Still, there won't be as many breaking
+changes as a "semver-major" version bump such as 3.2 -> 4.0.
+
+In the interest of stability and usability, patch releases may occasionally
+introduce small breaking changes as well. When repackaging Godot projects (e.g.
+in a Flatpak), make sure to always use the same patch version as the one used to
+initially export the project.
+
+.. note::
+
+    The first release in a major/minor release series doesn't end with a
+    trailing zero. For example, the first release in the 3.2 series is ``3.2``,
+    not ``3.2.0``.
+
+Release support timeline
+------------------------
+
+Godot versions are supported for a certain amount of time. While these durations
+are not set in stone, here's a table with the expected level of support
+for each Godot version:
+
++-------------+-------------------+--------------------------------------------------------------------------+
+| **Version** | **Release date**  | **Support level**                                                        |
++-------------+-------------------+--------------------------------------------------------------------------+
+| Godot 4.0   | ~2021 (see below) | |unstable| *Current focus of development (unstable).*                    |
++-------------+-------------------+--------------------------------------------------------------------------+
+| Godot 3.2   | January 2020      | |supported| Backwards-compatible new features (backported from the       |
+|             |                   | ``master`` branch) as well as bug, security, and platform support fixes. |
++-------------+-------------------+--------------------------------------------------------------------------+
+| Godot 3.1   | March 2019        | |partial| Only critical, security and platform support fixes.            |
++-------------+-------------------+--------------------------------------------------------------------------+
+| Godot 3.0   | January 2018      | |partial| Only critical, security and platform support fixes.            |
++-------------+-------------------+--------------------------------------------------------------------------+
+| Godot 2.1   | July 2016         | |partial| Only critical, security and platform support fixes.            |
++-------------+-------------------+--------------------------------------------------------------------------+
+| Godot 2.0   | February 2016     | |eol| No longer supported.                                               |
++-------------+-------------------+--------------------------------------------------------------------------+
+| Godot 1.1   | May 2015          | |eol| No longer supported.                                               |
++-------------+-------------------+--------------------------------------------------------------------------+
+| Godot 1.0   | December 2014     | |eol| No longer supported.                                               |
++-------------+-------------------+--------------------------------------------------------------------------+
+
+.. |supported| image:: img/supported.png
+.. |partial| image:: img/partial.png
+.. |eol| image:: img/eol.png
+.. |unstable| image:: img/unstable.png
+
+**Legend:**
+|supported| Full support -
+|partial| Partial support -
+|eol| No support (end of life) -
+|unstable| Development version
+
+Pre-release Godot versions aren't intended to be used in production and are
+provided on a best-effort basis.
+
+When is the next release out?
+-----------------------------
+
+While Godot contributors aren't working under any deadlines, there's usually a
+major or minor Godot release made available every year. Following this trend,
+this means Godot 4.0 will most likely be released in **2021**.
+
+Patch releases are made available more frequently, typically every 2-6 months
+while a release is fully supported. Partially supported releases will only have
+new patch releases once an important security or platform support fix has been
+merged.
+
+.. seealso::
+
+    The `roadmap <https://github.com/godotengine/godot-roadmap>`__ repository
+    documents features that have been agreed upon and may be implemented in future
+    Godot releases.