--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Sphinx/source/developers/db-versioning.rst	Fri Apr 22 12:57:38 2016 +0200
@@ -0,0 +1,51 @@
+.. _db-versioning:
+
+Database versioning
+===================
+
+Orthanc stores the index of the DICOM instances as an embedded `SQLite
+database <http://www.sqlite.org/>`_. The schema of this database has
+evolved across the versions of Orthanc, making the database
+incompatible between versions. This page clarifies which versions of
+Orthanc are compatible with other versions.
+
+Recent versions (post-0.3.1)
+----------------------------
+
+Recent versions of Orthanc (starting 0.3.1, inclusive) include
+information about the version of the DB schema in the SQLite table
+``GlobalProperties`` under the property with index 1. Versions with the
+same version of the DB schema are compatible with each other.
+
+When some version of Orthanc starts up, it checks whether it is
+compatible with the database version. Orthanc will **fail to start if
+it is not compatible with the database version**. Here is the
+compatibility matrix:
+
+===============================   =====   =====   =====   =====   =====
+Version                           DB v2   DB v3   DB v4   DB v5   DB v6
+===============================   =====   =====   =====   =====   =====
+Mainline                                  u       u       u       x
+Orthanc 0.9.5 - Orthanc 1.0.0             u       u       u       x
+Orthanc 0.8.5 - Orthanc 0.9.4             u       u       x
+Orthanc 0.7.3 - Orthanc 0.8.4             u       x
+Orthanc 0.4.0 - Orthanc 0.7.2             x
+Orthanc 0.3.1                     x
+===============================   =====   =====   =====   =====   =====
+
+*Note 1:* "u" means that an automatic upgrade of the DB schema is
+available, without having to :ref:`migrate the database
+<replication>`.
+
+*Note 2:* Starting with Orthanc 0.9.5, the option ``--upgrade`` must be provided
+on the command-line to allow Orthanc to upgrade the database schema.
+
+
+Early versions (pre-0.3.0)
+--------------------------
+
+Early versions of Orthanc (up to version 0.3.0, inclusive) **do not
+check the version** of the database schema. Because of this, these
+early versions are incompatible with all the other versions. Pay
+attention to the fact that no compatibility check is done in these
+versions, which may result in a corrupted database.