Microsoft will block some on-premise access to Office 365

Users of standalone Microsoft Office products will not be able to use Office 365 services such as Skype for Business, OneDrive for Business and Outlook from 2020.

Microsoft will only allow Office client connectivity from subscription clients (Office 365 ProPlus) or Office perpetual clients within mainstream support to connect to Office 365 services from 13 October 2020, the firm said in a blog post published last week.

The move affects users of standalone desktop versions of Office ranging from Office 2010 to Office 2016. Mainstream support for Office 2016 also ends on the same day as the new policy comes into effect.

This means that organisations will have to either purchase a version of Office that is still supported (right now, none will be by 2020), or buy an Office 365 subscription, as Microsoft pushes its customer base from one-off purchases towards subscriptions to its cloud productivity suite.

Alistair Speirs, senior operations product manager at Microsoft, blamed the move on the growing gap between Redmond's constantly-updated cloud software and the ageing on-premise software accessing it, saying that while the company updates system requirements for new on-premise apps and servers, it doesn't always do that when it upgrades its cloud products.

"In absence of that, we are sharing these system requirement changes as early as possible and as part of a larger discussion of the Office 365 ProPlus roadmap for deployment and management capabilities," he said.

Ron Markezich, corporate vice president for the Office commercial marketing team, added in another blog post that Microsoft was giving firms more than three years' notice to give IT departments time to plan and budget for this change.

"Until this new requirement goes into effect in 2020, Office 2010, Office 2013 and Office 2016 perpetual clients will still be able to connect to Office 365 services," he said.

The move affects individual users of Outlook, OneDrive or Skype, but not users who access web and mobile applications.

Microsoft is also changing the schedule of new updates to Office 365 with new features being delivered in March and September, roughly in tandem with similar updates to Windows 10.