Unfortunately, unlike WordPress, MediaWiki doesn’t come with a single-button update version. Perhaps because of that, perhaps because of my laziness, I have been postponing my updates of Wikimedia websites for over five years by now. However, in the light of recent vulnerability revelations, I have finally decided to upgrade my installations and started trying to figure what exactly I needed, given I only have web interfaces and FTP access to the website I manage.

First of all, this link gives a good overview of the whole process. For my specific case, I was upgrading to the 1.30, which required a number of edits to the config file, explained here. Now, what seemed to be happening was that after backing up my database (done for me by my hosting provider) and files (that I could to by FTP), I just needed to copy the files from the latest release version (REL1_30 in my case – DO NOT DO IT, see edit below) and copy it to the directories via FTP and then just run the database update script at wiki.mywebsite.org/mw-config/. Seems pretty easy, right?

Nope, not so fast! The problem is that this distribution does not contain a crucial directory that you need to run the installation and without which you wiki installation will fail with a 500 code without leaving anything in the error logs of the server.

This step isn’t really mentioned in the installation guide, but you actually need to remove the existing /vendor folder in your installation over FTP, build the latest version for your build with a git clone https://gerrit.wikimedia.org/r/p/mediawiki/vendor.git into a /vendor folder on your machine and then upload the files to your server.

Only after that step can you connect the /mw-config/ and finish upgrading the wiki.

So yeah, let’s hope that in a not-so-distant future MediaWiki would have the same handy ‘update now’ button as the WordPress. Because something is telling me that there are A LOT of outdated MediaWiki installs out there…

Edit:

After spending a couple additional hours dealing with additional issues: do not use the “core” build, but instead download the complete one, including all the skins, extensions and vendor files from here.