It includes the most collaborative, secure, and up-to-date features. Office 365 is the user-based subscription service powered by the Microsoft cloud. Office 2019 will receive quality and security patch updates as required. Office 2019 includes a subset of features found in Office 365, but it isn’t part of Office 365. Office 2019 is a one-time purchase and does not receive feature updates after purchase. What is the difference between Office 2019 (one-time purchase) and Office 365 (subscription)?.