The Omni Group released version 5.1 of and , adding localizations for 10 languages (including German, Spanish, French, Dutch, and Italian) and fixing numerous bugs related to filters, pasting, and more. Both editions of the outlining and information organization app change the process for converting a .oo3 file to a .ooutline file (automatically moving the .oo3 file to the Trash), update Essentials templates to include defined values for Heading 4-6, ensure that Column Inspectors always remain visible, improve the performance of HTML exporters (which are also used for Quick Look), and ensure that copying and pasting rows between OmniOutliner documents retains the Status value.
Shortly after the release of version 5.1, The Omni Group issued version 5.1.1 to fix a bug that prevented OmniOutliner from opening under OS X 10.11 El Capitan. OmniOutliner 5 is available from the as a free download (providing a 2-week free trial) with options for unlocking Essentials and Pro features at $9.99 and $59.99 respectively. ($9.99 new for Essentials, $59.99 for Pro, $4.99/$29.99 upgrades, 37.1 MB, , 10.11+)