You have to be prepared to Office 2016 Upgrade.
This is a reminder and beginning February 9, 2016, Office 2016 Current Branch for Business will be available. The First Release for Current Branch for Business has been available since September, and we are now making this broadly available to Office 365 customers.
[How does this affect me?]
Current Branch for Business is the default update branch of Office 2016, for Office 365 ProPlus subscriptions.
To upgrade from Office 2013 to Office 2016 requires planning and testing. If you’re an admin responsible for deploying Office 365 ProPlus in your organization, we want to provide you with information to help you prepare for and perform the upgrade.
We’ll be adding more guidance, but here are some things you can review in the meantime:
[What do I need to do to prepare for this change?]
We recommend that you review upgrade guidance and develop a plan to manage the upgrade of your existing Office 365 ProPlus installations. Auto-upgrades for Office 365 ProPlus and Office 365 Business clients will begin later in February 2016. If you wish to disable auto-upgrades refer to the following KB article: https://support.microsoft.com/en-us/kb/3097292.