Today we are happy to announce a public beta of a new plugin for Movable Type that helps users using Right Fields on Movable Type 3.x upgrade to Movable Type 4.2 using Custom Fields. There has been a great need in our community for this, which is why some of our veterans stepped up to assemble partial solutions to this problem. These solutions helped a great number of people, but were not able to address everyone's need universally, because the solution to this problem was not trivial. Recognizing this, we began a process with the community to identify and document what the ideal solution would look like. Then we implemented it so that users who felt they couldn't upgrade to Movable Type 4 could finally do so.
The plugin is called "Linked Entry Custom Fields" because the plugin does not exclusively help you migrate from Right Fields to Custom Fields. The plugin also provides your version of Movable Type Pro with an additional custom field type: linked entries. Linked entries, a feature native to Right Fields, provides a way for bloggers to establish relationships between related blog posts. You can imagine using this feature for example to help curate a list of related entries that you want to link to at the bottom of your post. So even if you have never used Right Fields, you may find some value in this plugin as well.
As with any beta, it is important for users to first make a backup of their system before beginning the migration and upgrade process. This is especially true with this plugin as there is a lot of data being moved around and there is potential for an unanticipated bug resulting in data loss. That being said, we would not be releasing this plugin now without having run a number of tests ourselves and feeling it was of sufficient quality to be released publicly.
To get started, visit the Linked Entry Custom Field page in the Plugin Directory.