Hello

We have been using MLF for over a decade on our site, but have (arrgh), sadly, never performed an upgrade.

Tststs, You are able until now to run the forum? Such an old version will at best run with PHP 5.x. Your hosting provider runs such an outdated PHP version? 😉 Anyway.

I've taken on the task to attempt to migrate whatever information is possible (within generous reason). Posts would be of greatest priority; everything else would be nice, but secondary.

We are currently at version 2.0.2.
I've installed the latest version (20220803.1) on a migration server, and (rightly or wrongly) assume that we don't want to attempt an upgrade in place.

Has anybody ever tackled such a project, or have any general or specific guidance on how to begin such an undertaking?

Ok, first things first. You can upgrade to the newest versions with a few interim steps.

1. Perform an update to version 2.3.5. This is directly possible, starting with version 2.0.2.
2. Afterwards perform an upgrade to version 2.4.24.

At this point you ar able to run the forum under PHP 7.4.

The last step is a bit tricky because we changed a few prerequisites but we didn't take attention to this change in the upgrade script. If you have e-mail-addresses, that are in use for more than one account, the upgrade will fail at the moment.

[edit]: If you are able to ensure that every e-mail-address in your userdata table is unique, an upgrade to 20220803.1 is possible.

Tschö, Auge