Device can be used for software. While there is a .manufactureDate element, that may not be appropriate for capturing the installation date for an instance of software (eg. an EHR system, an LIS). This should be added as a dateTime element. The definition should be clear if this is the date the software instance was install or when that instance was first used (eg. a go-live date). 

This field is necessary for the v2-to-FHIR project where SFT-6 is the install date.