Yesterday Microsoft announced that Windows 7, its follow-on version to Windows Vista, will be offered in six different versions. Today, Microsoft added more information by disclosing that existing Windows XP users will be able to upgrade to Windows 7. According to what information was available, the this will not be an in-place upgrade, but rather require a clean install, meaning all existing data will have to be backed up to avoid losing it. A Microsoft spokesperson confirmed that 'upgrade' refers to the license, meaning XP users will get discounted pricing but will get the full version of Windows 7. Not having to support an in-place upgrade means less development work for Microsoft, but could lead to lots of grief for users having to back up applications, settings and data prior to installing the new operating system. Microsoft has not released any details on pricing for any of the versions of Windows 7.