Manual:Upgrading



Overview
First read the UPGRADE text file included in MediaWiki.


 * 1) Check the requirements
 * 2) Read the release notes
 * 3) Back up existing files and the database
 * 4) Unpack the new files
 * 5) Run the update script to check the database
 * 6) Upgrade extensions
 * 7) Test the update

Check requirements
MediaWiki requires:

PHP

 * PHP 5.2.3 or later
 * We recommend using 5.2.x or 5.3.x, except 5.3.1,which has a bug preventing MediaWiki from functioning properly.

DBMS

 * MySQL 4.0.x or later
 * Version 3.x has not been supported since 1.6.0

or


 * PostgreSQL 8.3 or later
 * see also Upgrading Postgres

or


 * SQLite 3

Read the release notes
Within the distribution tarball, or within the files checked out/exported from SVN, there are a number of files with capitalised filenames, one of which contains the RELEASE-NOTES (wiki). Now's the time to open it up and find out what's been changed in this release.

Back up existing files and the database

 * Full instructions: Manual:Backing up a wiki

While the upgrade scripts are well-maintained and robust, things could still go awry. Before proceeding to update the database schema, make a full backup of the wiki, including both the database and the files:


 * the wiki's content, from the database. It may be a good idea to create an XML dump in addition to the SQL database dump.
 * MySQL:
 * SQL dump: mysqldump --all-databases > file.sql
 * XML dump: mysqldump --all-databases --xml > file.xml
 * PostgreSQL:
 * output for pg_restore: pg_dump --create -Fc -i yourwiki > yourwiki.db.dump
 * SQLite:
 * php maintenance/sqlite.php --backup-to filename
 * images and other media files (the contents of the images directory)
 * configuration files, e.g. LocalSettings.php and AdminSettings.php (if present)
 * MediaWiki's program files, including all skins and extensions, especially if you modified them.

Using a tarball package
If you are using a tarball package, decompress the file on the server where the old version of mediawiki is running. You may need to run the command as sudo if you don't have full write permissions to the wiki install directories under your current user. When untarring a tarball package normally a new directory for the new wiki version will be created and you will have to copy the new files and directories to your current wiki directory. Instead, to replace the existing files while decompressing and do this in one step, use this command:

$ tar xvzf mediawiki-.tar.gz -C /path/to/your/wiki/ --strip-components=1

On older Linux distributions (e.g. RHEL/CentOS 4.x) use:

$ tar xvzf mediawiki-.tar.gz -C /path/to/your/wiki/ --strip-path=1

People using an old version of tar (eg. GNU tar 1.13.x) which does not have --strip-components</tt> or --strip-path</tt> flags can uncompress the archive without the -C</tt> option and thereafter recursively copy the contents of the latest package into the previous wiki directory structure, as follows:

$ tar xvfz mediawiki-.tar.gz $ cp -r mediawiki-/* /path/to/your/wiki/

(Open)Solaris users should use gtar, or:

$ gzip -dc mediawiki-.tar.gz | tar xf -

Windows users: use 7zip to extract the tarball.

FTP users: extract files locally and upload directories and files to server.

Using Subversion
If using Subversion, export the files into a clean location. Replace all existing files with the new versions, preserving the directory structure. The core code is now up to date.

Files remaining that may cause errors
If you are not using profiling, but have a  file in the MediaWiki root folder, you may receive errors referring to. Deleting, or renaming, the  file will resolve this error. The  file, also in the MediaWiki root folder, can serve as a template should you enable profiling in the future.

Run the update script
You can upgrade MediaWiki either from the command line or from the web. If you have shell access to your server, upgrading from the command line is recommended, since this reduces the risk of the upgrade process being interrupted by a timeout or connection reset.

Command line
From the command line, or an SSH shell or similar, change to the maintenance</tt> directory and execute the update script:

$ php update.php

(Note for simple installations on Windows (e.g. with XAMPP): You can run the update.php by executing it (doubleclick) when your .php-files are associated with the PHP.exe (if not, rightclick update.php, select Open With and browse to PHP.exe). Ensure that your server-application (e.g. Apache) and your database (e.g. MySQL) are running. The resulting DOS window will likely autoclose).

MediaWiki will inspect the existing schema and update it to work with the new code, adding tables and columns as needed.

What to do in case of "No superuser credentials" error
In case the scripts abort with a message:

"No superuser credentials could be found. Please provide the details of a user with appropriate permissions to update the database. See AdminSettings.sample for more details"

This means that you should check that you have defined $wgDBadminuser and $wgDBadminpassword in your LocalSettings.php file (in the main directory). These are the user and password needed by this script in order to access to the database. (Note: Prior to MediaWiki 1.16, these variables were located in . This file was removed in 1.16 and the variables were moved to LocalSettings.php.)

What to do in case of "unexpected T_STRING" error
Individuals running update.php from the command line may encounter the following error: syntax error, unexpected T_STRING, expecting T_OLD_FUNCTION or T_FUNCTION or T_VAR or '}' \ in ~/maintenance/commandLine.inc on line 13

This error occurs when update.php is run from php4.

Individuals who have their site hosted by providers whom provide both php4 and php5 should take the following steps:
 * 1) from the command line, enter the command 'whereis php5'
 * 2) once you have discerned the location of the php5 path, list the contents of php5/bin directory
 * 3) once you've determined the name of the php executable (either php or php5), type in the entire path to execute update.php

Below is an example: $ whereis php5 $ ls -la /usr/local/php5/bin $ /usr/local/php5/bin/php update.php

Web updater
Do not use the web version if your database is already big. The update will take too long and the web server will kill the web request in the middle of the update. In this case, migrate your wiki to a hosting account with shell access and execute "php update.php" from within the /maintenance folder.


 * 1) Navigate to &lt;path-to-wiki&gt;/mw-config/index.php</tt>. For example, if your wiki is at  http://www.example.com/w/index.php </tt>, then navigate to  http://www.example.com/w/mw-config/index.php </tt>.
 * 2) Select your language and click continue.
 * 3) The existing installation should be detected. Follow the instructions on the screen to upgrade it. If asked for the upgrade key from LocalSettings.php, copy the value of $wgUpgradeKey and continue.

Upgrade extensions
Certain extensions have been updated in order to work with the new version of MediaWiki. Be sure to upgrade to the latest versions of such extensions. You might need to perform manual updates to custom extensions.

Test the update
Once the upgrade has been completed, browse to the wiki and check that the following operations work as expected:
 * Viewing pages
 * Editing pages
 * Uploading a file

Visit Special:Version and check that the version shown is correct and that the extensions are present.

How hard is it to upgrade?
If the only file you have modified is LocalSettings.php, and you are upgrading from 1.5 or later, the process is very simple. The amount of human work involved is only a few minutes. The database schema changes will take an amount of time proportional to the size of your database -- potentially hours for wikis with millions of pages, but for a more typical size of a few thousand pages, it is usually done in seconds.

Minor upgrades, within the same major version, say from 1.13.0 to 1.13.1, do not require any schema changes at all. You can just update the files. The database needs no update, hence it is not necessary to run the installer script.

Upgrading from 1.4 or earlier is potentially complicated because support for character sets other than UTF-8 was dropped, and the schema for storing bulk text changed. Please read the relevant section in the UPGRADE</tt> file.

Upgrading becomes difficult if you have modified our source code, and you don't want your changes to be overwritten. Tools such as diff and patch may be useful. There is also potential for trouble if you are using unmaintained extensions. Upgrade your extensions at the same time as you upgrade MediaWiki.

If you have modified the skin or use a custom skin you very likely will have to adjust it to work again with the new version of MediaWiki.

How do I upgrade from a really old version? In one step, or in several steps?
In one step, from your old version to the latest stable version. The vast majority of reports, as well as automated testing, indicate that doing it in one step works just fine.

If you have trouble believing this, read this mailing list post.

Should I back up first?
Short answer: Yes.

Long answer: It depends on a) how much you value your data, b) how hard it is to create a backup and c) how confident you are with MySQL maintenance and administration.

An upgrade failure may leave your database in an inconsistent state, in between two versions. It may move an important table to a temporary name and then fail before it recreates the table correctly. It may change a field definition to an incorrect data type. It is very rare for an upgrade to cause irreversible data loss. More often, data corruption occurs which can be reversed by a skilled administrator.

Recovery is often complex. Volunteers on the support forums are unlikely to be impressed if you neglect to make a backup and then need help to recover from upgrade-related corruption. A better outcome is if you can revert to your backup, and then report the bug in the upgrade process which caused the corruption.

Can I keep my LocalSettings.php?
Yes, but you may have to make some minor changes. The format of LocalSettings.php is largely backwards compatible. Changes which break LocalSettings.php compatibility will be documented in the "configuration changes" section of the release notes.

Can my wiki stay online while it is upgrading?
Yes.

If you are upgrading between minor releases of MediaWiki, all you need to do is update the source files.

Note: the following assumes you have command line access. If you are upgrading between major releases of MediaWiki, the preferred procedure is as follows:
 * 1) Unpack the new version of MediaWiki into a new directory
 * 2) Prepare that new directory: copy your current LocalSettings.php from the old directory, copy any installed extensions and custom skins (if any).
 * 3) In the release notes for the new version, see if any changes need to be made to LocalSettings.php.
 * 4) Place the database in read-only mode by inserting the following variable into LocalSettings.php in the old directory - users will see this message if they attempt an edit during the upgrade process:
 * 5) Run the update script in the new directory.
 * 6) Copy the images from the images sub-directory from the old directory to the new directory.
 * 7) Swap the old directory and the new directory.

Why upgrade?
Of course, every upgrade has security improvements that stop your wiki from getting hacked by vandals. In case you need additional arguments to convince your bosses to let you upgrade from a pretty old version:


 * As of MediaWiki 1.16, the user groups ACL system has an important improvement: you can now revoke rights.
 * Performance improvements. If you have appropriate caching, ResourceLoader optimizes pageload speeds a lot.
 * Category sorting makes sense!
 * As of 1.16, the new Vector skin looks nicer and is more moddable.
 * In MediaWiki 1.18 we started bundling some vital extensions, like a better editor and anti-vandalism tools ConfirmEdit and Nuke.