This policy setting allows you to set the number of days when all version history items created before this value will be deleted. With a 2016 format notebook, OneNote will automatically store previous versions of the pages in the notebook, and it will also store a recycle bin for all of the deleted pages and sections.
If you enable this policy setting, you can set the number of days back to delete version history.
If you disable or do not configure this policy setting OneNote will default to keeping previous versions for all days in the past. This is the default value of -1.