Publishers can set the licence validity for Purchase Orders (POs). This ensures that the content is accessible to users for a fixed number of days. The content will automatically be removed from the library of the user when the license validity expires. License validity can be assigned either by choosing a Start and Expiry Date or by choosing the Duration (number of days).Only expiry date/duration fields can be edited once a license has been created. In the case of school/district licenses, the license validity count starts from the license start date. In the case of an access code, if the license is created with Duration, then the start date of the licensee starts from the date when the user redeems the access code.  If the access code is created by the start date, then the start date of the license will start from the specified start date.Refer to Create school licenseRefer to Create access code