Okay, you have the green light and it's time to get cracking deploying Office 365. Before a mailbox can be migrated, before even an account can be AADSync'ed, before you even provision the O365 tenant, there is the matter of checking if the existing infrastructure is ready to handle the great features of Office 365.
What is always recommended before the design phase of a project even starts is to conduct an Office 365 readiness assessment. Working on a project recently and having it fresh in my mind, I thought I'd put finger to keyboard (pen to paper) and jot down the key items to check.
There's allot of IT companies out there who offer this discovery and assessment process which is great. As a handy reference point, here's the approach I take, with the a focus on Exchange Online messaging as that's what I'm pretty good at…
Sidebar: Office 365 Identity
A couple links to some interesting reads that might be of use:
These are most of the considerations related to the Office 365, more focused on the Exchange Online side. SharePoint Online and Lync Online have their own additional requirements and additional readiness assessment tasks on top of the above.
However, with the complexity that can be SharePoint Server, oftentimes using a third party tool like Share-Gate achieves the desired results with considerable less stress. The only hurdle is procurement of licensing for Share-Gate.
Finally, there is an overview of any Skype for Business infrastructure on-premises and extending that to the cloud, as well as understanding any social requirements to provision Yammer Enterprise.