It means that some issues might occur, since new versions can contain improvements and new functionalities. "XML stored with a newer BICS version (XML version 3.0, client version 2.0)" Whenever opening in AO 2.4 version (or lower), a workbook that was saved using AO 2.5 or higher version, the warning message below will occur:
See note 2917177 (Contains EPM Add-in SP37 patch 1. See note 2924387 (Contains EPM Add-in SP38. See note 2924400 (Contains EPM Add-in SP38 patch 1. See note 2927196 (Contains EPM Add-in SP38 patch 2. See note 2993485 (Contains EPM Add-in SP38 patch 3. See note 2993475 (Contains EPM Add-in SP38 patch 4. See note 2993498 (Contains EPM Add-in SP38 patch 5.