Steps

To upgrade an XWiki instance installed from the standalone (demo) distribution, install the new version beside the old one and move your data across:

1. Back up the configuration files, the permanent data (the /data directory, which already contains the HSQLDB database) and, optionally, the log files.
2. Check the Release Notes of every version between the one you are running and the one you are upgrading to, in particular the sections named "Issues specific to XWiki <version>" and any change to the prerequisites.
3. Download the new version as you did when installing the distribution.
4. Stop the XWiki instance, to prevent file corruption and database inconsistencies.
5. Install the new version in a different directory, keeping both installations.
6. Keep the new configuration files when you never customized the old ones, and otherwise merge the old files into the new ones instead of copying them over, since the new version may have added options.
7. Copy the data directory from the old instance to the new one.
8. Check that migrations are enabled, as described in Database Upgrade.
9. Start the new instance.
10. Upgrade the flavor from a browser, which the Distribution Wizard offers as soon as you log in.

The new instance then serves the content of the old one, which stays untouched in its own directory until you remove it.

FAQ

How to do the merge of the files on Unix operating systems?

If you are using a Unix system, some commands help you do the merge instead of doing it fully manually.

What if the migration of the database fails?

If the migration process fails, drop the DATABASECHANGELOG and DATABASECHANGELOGLOCK tables from your database and then restart the migration. This should allow the migration to proceed without further issues.

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