Important Notice: Changes to Microsoft 365, Office 365, and Microsoft Teams licensing.

So far, the way I read it, they aren't changing anything for existing customers who wish to continue as-is. That said, we've been here before and there is no reason to believe it won't be a required change for us at any point in the future. Note that missing from all of this is any timeframe on the statement that existing customers can continue with licensing as-is. 

Microsoft is second only to Google when it comes to changing the carpet under our feet.