The Office 365 suite of services, along with Office 365 ProPlus, is governed by the Modern Lifecycle Policy. Other Office products are governed by the Fixed Lifecycle Policy. Search for a specific Office product to see its corresponding Lifecycle Policy and end-of-support dates.
For Office on-premises products released after February 1, 2018, Microsoft will provide 5 years of mainstream support with 2 years of extended support as an exception to the 10-year Fixed-Lifecycle Policy term. This 7-year term will align with the support period for Office 2016.