https://support.esri.com/en-us/patches-updates/2016/migrating-mxds-in-business-analyst-desktop-from-9-3-1-t-1693
Migrating MXDs in Business Analyst Desktop from 9.3.1 to 10.0
This PDF document describes how to open existing 9.3.1 MXDs in Esri Business Analyst 10. There are two document options: a long version and a concise version.