added a new chapter about the Symfony release process

contributing/community/index.rst

@@ -4,5 +4,6 @@ Community
 .. toctree::
     :maxdepth: 2
 
+    releases
     irc
     other

contributing/community/releases.rst

@@ -0,0 +1,119 @@
+The Release Process
+===================
+
+This document explains the Symfony release process (Symfony being the code
+hosted on the main symfony/symfony `Git repository`_).
+
+Symfony manages its releases through a *time-based model*; a new Symfony
+release comes out every *six months*: one in *May* and one in *November*.
+
+.. note::
+
+    This release process has been adopted as of Symfony 2.2, and all the
+    "rules" explained in this document must be strictly followed as of Symfony
+    2.4.
+
+Development
+-----------
+
+The six-months period is divided into two phases:
+
+ * *Development*: *Four months* to add new features and to enhance existing
+   ones;
+
+ * *Stabilisation*: *Two months* to fix bugs, prepare the release, and wait
+   for the whole Symfony ecosystem (third-party libraries, bundles, and
+   projects using Symfony) to catch up.
+
+During the development phase, any new feature can be reverted if it won't be
+finished in time or if it won't be stable enough to be included in the current
+final release.
+
+Maintenance
+-----------
+
+Each Symfony version is maintained for a fixed period of time, depending on
+the type of the release.
+
+Standard Releases
+~~~~~~~~~~~~~~~~~
+
+A standard release is maintained for an *eight month* period.
+
+Long Term Support Releases
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Every two years, a new Long Term Support Release (aka LTS release) is
+published. Each LTS release is supported for a *three year* period.
+
+.. note::
+
+    Paid support after the three year support provided by the community can
+    also be bought from `SensioLabs`_.
+
+Schedule
+--------
+
+Below is the schedule for the first few versions that use this release model:
+
+.. image:: /images/release-process.jpg
+   :align: center
+
+ * *(special)* Symfony 2.2 will be released at the end of February 2013;
+
+ * *(special)* Symfony 2.3 (the first LTS) will be released at the end of May
+   2013;
+
+ * Symfony 2.4 will be released at the end of November 2013;
+
+ * Symfony 2.5 will be released at the end of May 2014;
+
+ * ...
+
+Backward Compatibility
+----------------------
+
+After the release of Symfony 2.3, backward compatibility will be kept at all
+cost. If it is not possible, the feature, the enhancement, or the bug fix will
+be scheduled for the next major version: Symfony 3.0.
+
+.. note::
+
+    The work on Symfony 3.0 will start whenever enough major features breaking
+    backward compatibility are waiting on the todo-list.
+
+Rationale
+---------
+
+This release process was adopted to give more *predictability* and
+*transparency*. Is was discussed based on the following goals:
+
+ * Shorten the release cycle (allow developers to benefit from the new
+   features faster);
+
+ * Give more visibility to the developers using the framework and Open-Source
+   projects using Symfony;
+
+ * Improve the experience of Symfony core contributors: everyone knows when a
+   feature might be available in Symfony.
+
+ * Coordinate the Symfony timeline with popular PHP projects that work well
+   with Symfony and with projects using Symfony;
+
+ * Give time to the Symfony ecosystem to catch up with the new versions
+   (bundle authors, documentation writers, translators, ...).
+
+The six month period was chosen as two releases fit in a year. It also gives
+plenty of time to work on new features and it also allows for non-ready
+features to be postponed to the next version without having to wait too much
+for the next cycle.
+
+The dual maintenance mode was adopted to make every Symfony user happy. Fast
+movers, who want to work with the latest and the greatest, use the standard
+releases: a new version is published every six months, and there is a two
+months period to upgrade. Companies wanting more stability use the LTS
+releases: a new version is published every two years and there is a year to
+upgrade.
+
+.. _Git repository: https://github.com/symfony/symfony
+.. _SensioLabs:     http://sensiolabs.com/

contributing/map.rst.inc

@@ -17,5 +17,6 @@
 
 * **Community**
 
+  * :doc:`Release Process </contributing/community/releases>`
   * :doc:`IRC Meetings </contributing/community/irc>`
   * :doc:`Other Resources </contributing/community/other>`