I upgraded the WordPress of this site, because WordPress.ORG released the newest Japanese version. It was really easy. All I needed is to upload the new files, then access to upgrade.php. I didn’t get any errors at that time. After I logged in, I activated WP Multibyte Patch plugin, which was automatically added, then checked that the other plugins were OK.
In addition, I installed xLanguage plugin to enable Japanese & English bilingual posts.
日本語
English
