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MediaWiki major upgrade process

Keeping your MediaWiki site up to date with the latest version is, like many sysadmin tasks, a never-ending chore. In a previous article I covered how to upgrade minor revisions of MediaWiki with patches. In this one, I'll cover my solution to doing a "major" upgrade to MediaWiki. While the official upgrade instructions are good, they don't cover everything.

MediaWiki, like Postgres, uses a three-section version number in which the first two numbers combined give the major version, and the number on the end the revision of that branch. Thus, version 1.26.2 is the third revision (0, then 1, then 2) of the 1.26 version of MediaWiki. Moving from one major version to another (for example 1.25 to 1.26) is a larger undertaking than updating the revision, as it involves significant software changes, whereas a minor update (in which only the revision changes) simply provides bug fixes.

The first step to a major MediaWiki upgrade is to try it on a cloned, test version of your wiki. See this article on how to make such a clone. Then run through the steps below to find any problems that may crop up. When done, run through again, but this time on the actual live site. For this article, we will use MediaWiki installed in ~intranet/htdocs/mediawiki, and going from version 1.25.3 to 1.26.2


Before making any changes, make sure everything is up to date in git. You do have your MediaWiki site controlled by git, right? If not, go do so right now. Then check you are on the main branch and have no outstanding changes. It should look like this:

$ cd ~/htdocs/mediawiki
$ git status
# On branch master
nothing to commit, working directory clean


Time to grab the new major version. Always get the latest revision in the current branch. For this example, we want the highest in the 1.26 branch, which as of this writing is 1.26.2. You can always find a prominent link on Make sure you grab both the tarball (tar.gz) and the signature (.tar.gz.sig) file, then use gnupg to verify it:

$ wget
$ wget
$ gpg mediawiki-1.26.2.tar.gz.sig 
gpg: assuming signed data in `mediawiki-1.26.2.tar.gz'
gpg: Signature made Sun 20 Dec 2015 08:13:14 PM EST using RSA key ID 23107F8A
gpg: please do a --check-trustdb
gpg: Good signature from "Chad Horohoe <>"
gpg:                 aka " <>"
gpg:                 aka "Chad Horohoe (Personal e-mail) <>"
gpg:                 aka "Chad Horohoe (Alias for existing email) <>"
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: 41B2 ABE8 17AD D3E5 2BDA  946F 72BC 1C5D 2310 7F8A

Copy the tarball to your server, and untar it in the same base directory as your mediawiki installation:

$ cd ~/htdocs
$ tar xvfz ~/mediawiki-1.26.2.tar.gz

Copy files

Copy the LocalSettings.php file over, as well as any custom images (e.g. the logo, which I like to keep nice and visible at the top level):

$ cp mediawiki/LocalSettings.php mediawiki-1.26.2/
$ cp mediawiki/Wiki_logo.png mediawiki-1.26.2/

Setup the images directory. The tarball comes with a dummy directory containing a few unimportant files. We want to replace that with our existing one. I keep the images directory a level up from the actual mediawiki directory, and symlink it in. This allows for easy testing and upgrades:

$ cd ~/htdocs/mediawiki-1.26.2
$ rm -fr images/ ## Careful, make sure you are in the right directory! :)
$ ln -s ../images/ .

Copy extensions

Now it is time to copy over the extensions. MediaWiki bundles a number of extensions in the tarball, as they are considered "core" extensions. We do not want to overwrite these with our old versions. We do want to copy any extensions that exist in our old mediawiki directory, yet not in our newly created one. To help keep things straight and reduce typing, let's make some symlinks for the existing (old) MediaWiki and for the current (new) MediaWiki, naming them "aa" and "bb" respectively. Then we use "diff" to help us copy the right extensions over:

$ cd ~/htdocs
$ ln -s mediawiki aa
$ ln -s mediawiki-1.26.2 bb
## Visually check things over with:
$ diff aa/extensions bb/extensions | grep 'Only in aa' | awk '{print $4}' | more
## Do the copying:
$ diff aa/extensions bb/extensions | grep 'Only in aa' | awk '{print $4}' | xargs -iZ cp -r aa/extensions/Z bb/extensions/Z

Extensions may not be the only way you have modified your installation. There could be skins, custom scripts, etc. Copy these over now, being sure to only copy what is truly still needed. Here's one way to check on the differences:

$ cd ~/htdocs
$ diff -r aa bb | grep 'Only in aa' | more

Check into git

Now that everything is copied over, we can check the 1.26.2 changes into git. To do so, we will move the git directory from the old directory to the new one. Remember to let anyone who might be developing in that directory know what you are doing first!

$ mv aa/.git bb/
## Don't forget this important file:
$ mv aa/.gitignore bb/
$ cd mediawiki-1.26.2
$ git add .
$ git commit -a -m "Upgrade to version 1.26.2"
$ git status
# On branch master
nothing to commit, working directory clean

Extension modifications

This is a good time to make any extension changes that are needed for the new version. These should have been revealed in the first round, using the cloned test wiki. In our case, we needed an updated and locally hacked version of the Auth_remoteuser extension:

$ cd ~/htdocs/mediawiki-1.26.2/extensions
$ rm -fr Auth_remoteuser/
$ tar xvfz ~/Auth_remoteuser.tgz
$ git add Auth_remoteuser
$ git commit -a -m "New version of Auth_remoteuser extension, with custom fix for wpPassword problem"

Core modifications

One of the trickiest part of major upgrades is the fact that all the files are simply replaced. Normally not a problem, but what if you are in the habit of modifying the core files because sometimes extensions cannot do what you want? My solution is to tag the changes prominently - using a PHP comment that contains the string "END POINT". This makes it easy to generate a list of files that may need the local changes applied again. After using "git log" to find the commit ID of the 1.26.2 changes (message was "Upgrade to version 1.26.2"), we can grep for the unique string and figure out which files to examine:

$ git log 1a83a996b9d00444302683fb6de6e86c4f4006e7 -1 -p | grep -E 'diff|END POINT' | grep -B1 END
diff --git a/includes/mail/EmailNotification.php b/includes/mail/EmailNotification.php
-        // END POINT CHANGE: ignore the watchlist timestamp when sending notifications
-        // END POINT CHANGE: send diffs in the emails
diff --git a/includes/search/SearchEngine.php b/includes/search/SearchEngine.php
-       // END POINT CHANGE: Remove common domain suffixes

At that point, manually edit both the new and old version of the files and make the needed changes. After that, remember to commit all your changes into git.

Final changes

Time to make the final change, and move the live site over. The goal is to minimize the downtime, so we will move the directories around and run the update.php script on one line. This is an excellent time to notify anyone who may be using the wiki that there may be a few bumps.

## Inform people the upgrade is coming, then:
$ mv mediawiki old_mediawiki; mv mediawiki-1.26.2 mediawiki; cd mediawiki; php maintenance/update.php --quick
$ rm ~/htdocs/aa ~/htdocs/bb


Hopefully everything works! Time to do some testing. First, visit your wiki's Special:Version page and make sure it says 1.26.2 (or whatever version you just installed). Next, test that most things are still working by:

  • Logging in, and...
  • Editing a page, then...
  • Upload an image, plus...
  • Test all your extensions.

For that last bullet, having an extension testing page is very handy. This is simply an unused page on the wiki that tries to utilize as many active extensions as possible, so that reloading the page should quickly allow a tally of working and non-working extensions. I like to give each extension a header with its name, a text description of what should be seen, and then the actual extension in action.

That's the end of the major upgrade for MediaWiki! Hopefully in the future the upgrade process will be better designed (I have ideas on that - but that's the topic of another article). One final check you can do is to open a screen and tail -f the httpd error log for your site. After the upgrade, this is a helpful way to spot any issues as they come up.

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