Microsoft will support companies that keep their data on premises, though it will also encourage those same customers to move data to the cloud whenever possible.
The Microsoft roadmap includes the next on-premises version of its venerable Exchange messaging server. Exchange 2019 goes into preview in mid-2018, with the official rollout expected in late 2018 or early 2019. If Microsoft sticks to its traditional product release cadence, look for Exchange 2019 availability in October 2018.
Businesses that want an early look at Exchange 2019 can apply for the Exchange On-Premises Technology Adoption Program. It's unclear if a migration from Exchange 2010 to Exchange 2019 will require two steps, as it did for moves from Exchange 2007 to Exchange 2016.
Microsoft will release Office 2019 in the second half of 2018 with a preview expected by the middle of the year. Office 2019 will include the standard business applications, such as Word, Excel, PowerPoint and Outlook. Office 2019 is geared to enterprises that aren't ready for or can't move to the cloud and will likely include features already available to Office 365 ProPlus adoptees.
Office 2019's capabilities will include improved inking features, more powerful data analysis formulas and charts in Excel, visual animation features for PowerPoint and updates to IT manageability, usability, voice and security.