I've got a client that's running a pretty ancient version of Mediawiki (1.17.0) on an internal corporate network. It's running on PHP5, but they're looking to upgrade to PHP7. This version has basically served its purpose well and whoever was in charge never messed with upgrading it. (I know) But it won't run under PHP 7.4 and the company is upgrading their PHP systems.
Obviously there have been a TON of revisions to MediaWiki in this time. I've got a few questions...
First, what's the earliest version of MediaWiki that is PHP7 compatible?
Second, what's the best approach to updating this system? It's got over 1000 pages and 1000 images. It's not huge, but it's obviously not small, and if there's any way to automate bringing this up to the most current version, I'm curious what my options are?
I'm trying to avoid doing incremental updates because upon investigating, it's a ton of them, and not all interim versions seem to be available.
Is it possible to install a new, fresh version and copy the database/images over?
Any advice is most appreciated!
As noted in https://www.mediawiki.org/wiki/Compatibility#Upgrade , you need to upgrade first to 1.35 and then to 1.38 (or 1.39 if you wait a little - 1.39 is an LTS release so probably worth it). See the manual on upgrading on how to do it - basically, update the files in MediaWiki core and all extensions, possibly run
composer updatedepending on your distribution (tarballs tipically already include the files that Composer would download, git doesn't), and run the upgrade script wich will migrate the DB.