A 200,000-post forum taken from phpBB 3.0.8 to 3.3.5

A large board on an outdated version, with a custom theme and custom plugins, moved forward across several major releases in one go.

The objective

The board had around 200,000 posts, a custom theme and several custom plugins, and was still sitting on phpBB 3.0.8. The theme had to move to 3.3 as well, which in phpBB means a different template system, not just a version bump.

The plugin list needed reviewing rather than migrating wholesale. Some had upstream replacements and some weren't worth keeping anymore.

What I did

I ran the upgrade on a copy first to find where a board that size would time out or fail.

I rebuilt the custom theme against the 3.3 template structure rather than trying to patch the old one forward.

I went through the custom plugins with the client and decided, one at a time, whether to port, replace or drop each one.

Then I ran the live upgrade once the copy went through cleanly.

The result

The board came out on 3.3.5 with its posts, its look, and the plugins that were worth keeping.