What to Watch Out for When Upgrading Custom Fields »
If your Movable Type installation uses extra fields and you want to use MT4, then at this point, you really only have one option - Custom Fields. The plugin, currently in something of a perpetual beta because Arvind is in the US for school, allows you to easily add fields to just about any object in the system. It's actually quite nice.
But if you have already been using Custom Fields, you might find yourself in a bit of a pickle when it comes to upgrading your data and you've found that the data you have been trying to keep from losing is suddenly no longer there. Luckily, the upgrade path isn't a bad one, nor is it particularly painful. You just have to be very careful when you decide to upgrade your installation.
