An old board rebuilt on phpBB 3.3 with its data carried over

A phpBB 3.0.14 site with an old theme and a set of mods that no longer ran on current versions. The client was open to either an in-place upgrade or a fresh install with the data moved in.

The objective

The site ran phpBB 3.0.14 with an old UI theme and a number of mods that wouldn't work on 3.3. There were two routes: upgrade in place and try to hold onto the theme and mods, or install 3.3 fresh with a new theme and migrate the old database into it.

Which one is right comes down to how much of the old customisation is actually worth keeping, so that was the first thing to settle.

What I did

I went through the installed mods to see which had current equivalents and which had no path forward at all.

I set up the target 3.3 install and customised the theme the client picked.

I migrated the database across, keeping every post and user account.

Then I checked the board for the things that usually go wrong in a jump this large: attachments, permissions and search indexes.

The result

The forum ended up on a supported version with all of its history, and without time burned rebuilding mods that weren't worth rebuilding.