Existing Microsoft Business Productivity Online Standard Suite (BPOS) customers are being transitioned by the our transition team to Microsoft Office 365. During this transition the Microsoft Transition team will move all existing BPOS SharePoint Online site collections to Office 365 per tenant.
For information about how to prepare for this transition, see the “Microsoft Online Services transition center” – link.
If your BPOS SharePoint Tenant was recently transitioned to Office 365, there may be steps you need to take to resolve some common issues that can happen – see the “SharePoint Online Post-Transition Guide: BPOS to Office 365” for more information – link
See also BPOS to Office 365 Transition Guide from february 2012 – link