Sage 50 2021 will allow users to email, send documents to Excel, and Write Letters, while a user has Microsoft 365 Personal. The requirement of Microsoft 365 Business Premium with Sage 50 2021 allows users to take advantage of various Sage 50cloud connected functionalities including Sage Contact, Sage Dashboard, Sage Capture, Sage Approvals, Sage Intelligence, Cloud Backup, and Sage Business Center. If you do not want to take advantage of any of these Microsoft 365 Connected Apps, then you can use Microsoft 365 Personal with Sage 50 2021 for the basic Microsoft 365 integration.