admin/environment/unicode

See the unicode page for background information about unicode and UTF-8.

Prior to 1.6, Moodle did not support UTF-8 across all languages and the encoding in which the data was stored in the database depended upon the language used in a particular course. From Moodle 1.6 onwards, all language packs are converted to UTF-8 and different languages may be used on the same page. Moodle 1.6 and 1.7 include a utility to migrate your database from any encoding to UTF-8.

From Moodle 1.8 onwards, the database migration utility is no longer included, as it is assumed that you upgrade from a UTF-8 encoded database.

Thus, if you wish to upgrade from 1.5 or an earlier version, you must first upgrade to 1.6 or 1.7, migrate your database to UTF-8, and then upgrade to 1.8. Similarly, if you are using Moodle 1.6 or 1.7 and have not yet migrated your database, you need to do so before upgrading to 1.8. Please refer to Upgrading to Moodle 1.6 for additional information.