How to upgrade a Plone site to a newer version

1. Stop Plone / Zope

2. Backup your Plone site, just in case. You should backup:

    * your Data.fs which contains your site data
    * any file system files in which you have modified
    
3. Install the new version of Plone, this depends upon your installation. Newest
   versions of Plone are always available from http://plone.org/downloads and
   your install will depend upon your particular setup. Generally you should
   replace the products with the products from the CMFPlone archive. See
   INSTALL.txt for more informations.

4. Restart Plone / Zope

5. For each Plone site enter the ZMI and go to portal_migrations and click on
   the migrate tab. Click the migrate button to migrate your instance to the
   version you have just downloaded.

Running a migration may:

 * change values you have set in the ZODB such as actions, properties skins and such

 * mean a recataloguing of your portal_catalog, this may be time consuming

 * reapplying security to objects, this may be time consuming

If you have issues please search for an update of your python, zope, plone and 
third-party products and read http://plone.org/development/current/projects/Plone20Migration.
If you still have issues please the use the bug tracker at http://plone.org/collector
and include: your Zope, CMF and Python versions, the platform, the CMFPlone 
versions you are migrating to and from and *important* the full traceback and
migration log. Try to provide as much informations as possible.
