If anyone out there has already developed some SharePoint sites with beta release and now want to move to RTM then there’s a bad news. The migration is not supported. If you try to move your content with Content Migration API then you’ll get an error message like below:
The Version of the package 14.0.4536.1000 differs from the current version 14.0.4762.1000 which is supported by this program.
Steve Chen has described in his blog on why the migration from beta to RTM is not supported. He mentioned that the lesson Sharepoint team learned from 2007 that there may be inconsistency data left from pre-releases versions. These inconsistent data (from pre-release versions) may generate problems for later releases. However, customers having “Go-Live” license can get help from Microsoft to move data from beta to RTM. The “Go-Live” license is an agreement between customers and Microsoft to help customers to migrate from beta to RTM.
The final learning is “Play with beta releases but don’t dear to develop production code until final version is released”.
Related information can be found in the following links: