In June 2007, Microsoft announced a new version of the office suite, Office Mobile 2007. It became available as "Office Mobile 6.1" on September 26, 2007 as a free upgrade download to current Windows Mobile 5.0 and 6 users. However, "Office Mobile 6.1 Upgrade" is not compatible with Windows Mobile 5.0 powered devices running builds earlier than 14847. It is a pre-installed feature in subsequent releases of Windows Mobile 6 devices. Office Mobile 6.1 is compatible with the Office Open XML specification like its desktop counterpart.