First of all, I'm not familiar with Azure Office 365 and see if I can just for one step migration without downtime.
We have AD with forest and domain functional level 2003 and Exchange server 2003.
There are not many users for this small business, about 70 user mailboxes.
I have to suggest my boss which way is better to go either on-premise or Azure office 365.
For on-premise, as I researched, I have to go through two step upgrades for AD and exchange server, 2008 -> 2016.
Instead, is it possible just go directly from on-premise exchange 2003 to Office 365? If then, how does it work with our current AD? Do I still raise forest/domain functional level to 2012? I am trying to figure what is the damage during the upgrade because this business is 24 hour operation, have to minimize the downtime.