Transition from Office 365 Midsized Business to Business Premium

Hi All,

We have been using O365 Midsized since end of 2014 and recently found that we need to move to the new plans as Midsized will no longer exist. We are going to move to Business Premium and wanted to check if anyone has gone through this transition yet, and any issues or things to plan for.

From our local reseller they said we would lose email aliases for all users and also mailbox delegation will be lost too, but I can't find this anywhere in MS or Office 365 KB's.Is this accurate info??

I know we'll lose MS Access and few Excel features which is ok.

Thanks all

Art