View source for Manual:Upgrading

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== Basic overview ==

=== File transfer ===
Unless you have direct access to the server hosting the wiki, (and even then) you will have to choose a method for transferring files:
*Secure copy with [http://www.chiark.greenend.org.uk/~sgtatham/putty/download.html SCP] or [[w:WinSCP|WinSCP]]
*[[Wikipedia:SSH File Transfer Protocol|SSH File Transfer Protocol]] (SFTP)
*Using a [[w:File Transfer Protocol|FTP]] client.
*The hosting company might provide a file manager interface via the web browser; check with your provider.
*Some other method. There is a list of these at [[Wikipedia:List of file transfer protocols]]

===Preliminary=== 
Read {{git file|project=mediawiki/core|branch={{MW stable release git}}|file=UPGRADE|text=the UPGRADE text file included in MediaWiki}}.

# ''Check the requirements''
# ''Read the release notes''
# ''Back up existing files and the database''
# ''Unpack the new files''
# ''Upgrade extensions''
# ''Run the update script to check the database''
# ''Test the update''

== Check requirements == 

MediaWiki {{MW stable branch number}} requires:

* '''PHP {{MW stable php requirement}} or later'''
* Either '''MySQL {{MW stable mysql requirement}} or later''', '''PostgreSQL 8.3 or later''' or  '''SQLite 3'''

If you are using PostgreSQL, please also read [[Manual:Upgrading Postgres|Upgrading Postgres]].

For more information, please read the [[Manual:Installation requirements|system requirements]] and [[compatibility]].

== Read the release notes ==

Within the distribution tarball, or within the files checked out/exported from [[Git]], there are a number of files with capitalised filenames, one of which contains the '''{{git file|project=mediawiki/core|branch={{MW stable branch git}}|file=RELEASE-NOTES-{{MW stable branch number}}|text=RELEASE-NOTES}}''' ([[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 [[Manual:Backing up a wiki|backup]]''' of the wiki, including both the database and the files: 

* the wiki's content, from the database, (make sure you get the character set specified correctly, first check LocalSettings.php). It may be a good idea to create an XML dump in addition to the SQL database dump.
** MySQL:
*** SQL dump: <tt>mysqldump --user=xxx --password=xxx <database name> > file.sql</tt>
*** XML dump: <tt>mysqldump  --user=xxx --password=xxx <database name> --xml > file.xml</tt>
** PostgreSQL:
*** output for pg_restore: <tt>pg_dump --create -Fc -i yourwiki > yourwiki.db.dump</tt>
** SQLite:
*** <tt>php maintenance/sqlite.php --backup-to filename</tt>
* images and other media files (the contents of the <tt>images</tt> directory, custom logo /skins/common/images/wiki.png)
* configuration files, e.g. <tt>LocalSettings.php</tt> and <tt>AdminSettings.php</tt> (if present)
* MediaWiki's program files, including all skins and extensions, especially if you modified them.

== Unpack the new files ==

=== Using a tarball package ===
{{Note|If you extract the new version of MediaWiki directly on top of your old version, rather than in a new directory, you should follow [[#Back up existing files and the database]]: otherwise, if you've made any customizations you may erase them in a way that leaves you with no reference to re-apply them from. Extracting a tarball over top of your live copy of MediaWiki can leave behind files from the old version of MediaWiki which may interfere with the upgraded code. It's recommended that you unpack the new files into a new directory, and then apply customizations to the new directory (restoring LocalSettings.php, images folder, extensions, and other customizations like custom skins)}}

If you are using a [[download|tarball package]], decompress the file on the server, preferably on a new and empty folder.

==== FTP or graphical ====

Windows users: use [http://www.7-zip.org/download.html 7zip] to extract the tarball.

FTP users: extract files locally and upload directories and files to server with your favorite FTP software.

==== Command line ====

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 old configuration files and images directory from your old installation directory:

 $ tar xvzf mediawiki-{{MW stable release number}}.tar.gz -C /path/to/your/new/installation/

(Open)Solaris users should use gtar, or:

 $ gzip -dc mediawiki-{{MW stable release number}}.tar.gz | tar xf -

Once done, you should copy or move some files and folders from the old installation directory to the new one:
* LocalSettings.php, which contains your old configuration settings.
* the image file containing the logo, usually on upper left hand corner.
* The <code>images</code> (or <code>uploads</code> in older versions) directory, which contains all the uploaded files to the wiki, unless you have chosen a different upload directory.

Other files and folders you might want to update from the old installation:
* Some extensions in the <code>extension</code> directory. You should always get updated extensions, old extensions aren't guaranteed to work with a newer version of MediaWiki.
* Custom skins.
* Any modifications made to the old installation files.
* Any .htaccess file (if you're using Apache and you've defined any rule on it).

Once done, make this new folder the published folder on the web server, or rename the old installation directory and then rename the new one matching the old name.

=== Using Git ===
If using [[Download from Git|Git]], export the files into a clean location, and then copy the old customized files into the new location as described on the previous section.

=== Using patch ===
A small patch file is usually made available for a minor version upgrade. Manually download and extract the patch file from [http://dumps.wikimedia.org/mediawiki/ the dumps site] or follow the directions with wget below.

# cd to your main MediaWiki directory (the one with LocalSettings.php).
# Download the patch file (''e.g.'', <code>wget http://dumps.wikimedia.org/mediawiki/{{MW stable branch number}}/mediawiki-{{MW stable release number}}.patch.gz</code> ) and gunzip it.
# Use <code>patch -p1 --dry-run</code> to check what will be changed (''e.g.'', <code>patch -p1 --dry-run < mediawiki-{{MW stable release number}}.patch</code> )
# If all is well, run patch again without <code>--dry-run</code>.
# Check your Special:Version and you should see the new version number in place.

=== Files remaining that may cause errors ===
If you unpacked over the old installation directory, some old files can cause problems with the new version.

{{MW 1.18|and after}}
If you are not using [[Manual:Configuration settings#Profiling|profiling]], but have a <code>StartProfiler.php</code> file in the MediaWiki root folder, you may receive errors referring to <code>/includes/Profiler.php</code>.  Deleting, or renaming, the <code>StartProfiler.php</code> file will resolve this error.  The <code>StartProfiler.sample</code> file, also in the MediaWiki root folder, can serve as a template should you enable profiling in the future.

== 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.

Different [[tarballs]] include some subsets of extensions and have versioning which helps you upgrade choosing the right one for your MediaWiki core release.

[[Special:ExtensionDistributor|Extension Distributor]] works well for most people who want a snapshot of extensions that will work with their supported versions of MediaWiki.

If you want a lot of extensions then [[Download from Git|downloading from Git]] is probably best.

== Run the update script ==
<!--

NOTE TO EDITORS: As of r72451 <http://www.mediawiki.org/wiki/Special:Code/MediaWiki/72451>, this section name is linked from an error message hardcoded into MediaWiki, so if you change the section name, add <span id="Run_the_update_script"></span> or something so that the links still works.

-->

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 ===

Access the command line of your server or an SSH shell or similar. You can access the command line by connecting to your server via SSH. If the local PC you are working on runs Microsoft Windows, you will need a tool like [http://www.chiark.greenend.org.uk/~sgtatham/putty/download.html PuTTY] to use SSH. From the command line or the Shell, change to the <tt>'''maintenance'''</tt> directory and execute the [[Manual:update.php|update script]]:

 $ php update.php

Note for simple installations on Windows (e.g. with [[Manual:Installing MediaWiki on XAMPP|XAMPP]]):
First make sure that your web server (such as Apache) and your database (such as MySQL) are running.
Then run update.php: right-click it, select Open With, and browse to PHP.exe.
The resulting command prompt window will likely autoclose when the schema upgrade completes.

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:
<pre>
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"
</pre>
This means that you should check that you have defined [[Manual:$wgDBadminuser|$wgDBadminuser]] and [[Manual:$wgDBadminpassword |$wgDBadminpassword ]] in your [[Manual:LocalSettings.php|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 <code>[[Manual:AdminSettings.php |AdminSettings.php]]</code>. 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:
<pre>
syntax error, unexpected T_STRING, expecting T_OLD_FUNCTION or T_FUNCTION or T_VAR or '}' \
in ~/maintenance/commandLine.inc on line 13
</pre>

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

Individuals who have their site hosted by providers who provide both php4 and php5 should take the following steps:
# from the command line, enter the command 'whereis php5'
# once you have discerned the location of the php5 path, list the contents of php5/bin directory
# 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:
<pre>
$ whereis php5
$ ls -la /usr/local/php5/bin
$ /usr/local/php5/bin/php update.php
</pre>

====What to do in case of 'register_argc_argv is set to false' error====
You may encounter the error:
<pre>
Cannot get command line arguments, register_argc_argv is set to false
</pre>

# Go to ~/maintenance. Either edit an existing 'php.ini' file, or create one. 
# Add a line as follows:
<pre>
register_argc_argv=true
</pre>
# Re-run php update.php

===Web updater===
{{MW 1.17|and after}}
: ''See also [[Manual:update.php|update.php]]''
If your database is already big and in high production usage, then you should not be using the Web updater, e.g. because the update process will time out when the ''maximum_execution_time'' is reached. In that case you should use [[update.php]] from the command-line interface (not from the web). What exactly is "too big" depends on your server (e.g. on its performance, the load and on how long the maximum execution time of PHP allows the script to run). If your wiki is too big for the web updater and your hosting provider does not allow command-line access, then you need to migrate your wiki to another hosting account, preferably to one that does have shell access.

# Always [[Manual:Backing up a wiki|backup]] before performing database maintenance.
# Navigate your webbrowser to <tt>'''/mw-config/'''</tt>. For example, if your wiki is at <tt><nowiki>http://example.org/w/index.php</nowiki></tt>, then navigate to <tt><nowiki>http://example.org/w/mw-config/</nowiki></tt>.
# Select your language and click continue.
# The existing installation should be detected. Follow the instructions on the screen to upgrade it.<br/>If asked for the "upgrade key", open your [[Manual:LocalSettings.php|LocalSettings.php]] file and look for the key assigned to [[Manual:$wgUpgradeKey|$wgUpgradeKey]].

== 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.

== Frequently asked questions ==
<section begin=FAQ />
===How hard is it to upgrade?===
If the only file you have modified is [[Manual:LocalSettings.php|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 <tt>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 [http://www.gnu.org/software/diffutils/diffutils.html diff], [http://www.gnu.org/software/patch/ patch], [http://meldmerge.org/ Meld] or [http://winmerge.org/ WinMerge] 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.
: Tip: instead of patching your "global" css and js (javascript) files everytime you can simply add the code to your MediaWiki:Common.js and MediaWiki:Common.css pages. As these are part of the database which will be reused when you upgrade, you will not have to patch the MediaWiki core files any more.

===How do I upgrade from a really old version? In one step, or in several steps?===
It depends: If you are upgrading from MediaWiki 1.4 or older, you should upgrade to MediaWiki 1.5 first. If you are upgrading from a Latin-1 wiki, use upgrade1_5.php (found in MediaWiki 1.5) to convert the relevant parts of the database to UTF-8 ([[Manual:$wgUseLatin1|$wgUseLatin1]] needs to be set to true in your [[LocalSettings.php]] for this to work). Next, run update.php, and then set the [[Manual:$wgLegacyEncoding|$wgLegacyEncoding]] option in LocalSettings.php to the encoding previously used by the wiki (e.g. windows-1252). This is basically how Wikipedia and other Wikimedia Foundation sites were upgraded from MediaWiki 1.4 to 1.5 – see the [[http://noc.wikimedia.org/conf/highlight.php?file=InitialiseSettings.php relevant settings file (warning: huge page!)] and some [[wikitech:1.5 upgrade|related notes at Wikitech]]. You may need to upgrade to MediaWiki 1.4 before running the upgrade1.5 script.

If you are upgrading from MediaWiki 1.5 or newer, you can upgrade 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 [[mailarchive:mediawiki-l/2008-October/028975.html|this mailing list post]].

If upgrading from a MediaWiki version below 1.19, you may need to add the sha1 field to the [[Manual:revision table|revision table]] manually before running the update script (see [[bugzilla:48820|bug 48820]]  and a [[Thread:Project:Support desk/upgrade problems: 1.11 -- 1.21|relevant support desk thread]]).

===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 [https://bugzilla.wikimedia.org/enter_bug.cgi?product=MediaWiki 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 [[Manual:LocalSettings.php|LocalSettings.php]] is largely backwards compatible. Changes which break LocalSettings.php compatibility will be documented in the "configuration changes" section of the [[Release notes|release notes]].

===Can my wiki stay online while it is upgrading?===
Generally yes, however Git may temporarily (for a few seconds) break it.

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: 
# Unpack the new version of MediaWiki into a new directory
# Prepare that new directory: copy your current LocalSettings.php from the old directory, copy any installed extensions and custom skins (if any).
# In the release notes for the new version, see if any changes need to be made to LocalSettings.php.
# 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:<br/><code>[[Manual:$wgReadOnly|$wgReadOnly]] = 'Upgrading to MediaWiki {{MW stable release number}}';</code>
# Run the [[Manual:Upgrading#Command_line|update script]] in the new directory.<br/>
# Copy the images from the images sub-directory from the old directory to the new directory.
# Swap the old directory and the new directory.

===Why upgrade?===
:''Subscribe to [[mail:mediawiki-announce|mediawiki-announce]] to be notified of new releases.
Because it's [[#How hard is it to upgrade?|usually easy enough]], [[#How do I upgrade from a really old version? In one step, or in several steps?|a single step from your version to latest]] and also [[Manual:Upgrading#Web updater|via web]].

Many upgrades solve security issues which help to keep your wiki and possibly even your host system safe from vandals, while old releases are not supported (see [[Version lifecycle]]). New major releases come with new features, which you might want to use. See the release notes for details. In case you need additional arguments to convince your bosses to let you upgrade from a pretty old version:

* Since 1.9, an [[Release_notes/1.9#Undo_revision|undo button]] is available.
* Since 1.12, [[Help:Patrolling|patrolling]] on [[Special:NewPages]] is much easier.
* Since 1.13, you can [[Help:Moving a page|rename]] (move) files.
* Since 1.14, you can [[Manual:$wgFixDoubleRedirects|fix double redirects]] automatically.
* Since 1.16, [[InstantCommons]] is available.
* If you have appropriate caching, since 1.17 [[ResourceLoader]] optimizes pageload speeds a lot.
* Since 1.17, [[MediaWiki_1.17/Category_sorting|category sorting makes sense!]] (especially for non-English letters).
* In [[MediaWiki 1.19|1.19]] the skinning system was reworked making it easier to reuse parts of existing skins in your own skins.
* Since [[MediaWiki 1.18|1.18]] and [[MediaWiki 1.19|1.19]], users of all languages and genders are correctly addressed by the interface and [[m:Help:Special_page#Logs|logs]] (before 1.15, no gender at all).
* Since [[MediaWiki 1.20|1.20]], [[m:Help:Diff|diffs]] are better readable.

See also the [https://bugzilla.wikimedia.org/buglist.cgi?cmdtype=dorem&remaction=run&namedcmd=Most%20voted%20fixes&sharer_id=7541 list of the most voted fixed issues] on [[bugzilla]].

Also, in [[MediaWiki 1.18]] we started [[Suggestions_for_extensions_to_be_integrated|bundling some vital extensions]], like a better editor and anti-vandalism tools ConfirmEdit and Nuke.
<section end=FAQ />

== See also ==
*[[Project:Support desk]] if you need help or something went wrong
*[[Manual:Backing up a wiki]]
*[[Manual:Restoring a wiki from backup]]
*[[Manual:Moving a wiki]]
*[[Manual:Restoring wiki code from cached HTML]] (if you don't have a successful backup)
*[[Manual:Installing]]

[[Category:MediaWiki administration|{{PAGENAME}}]]
[[Category:MediaWiki for site admins]]

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