MS Office 2016, currently the youngest member of Microsoft’s Office family, was launched in the second half of 2015. A release of 5 years will be supported from this release on. In this mainstream support phase, Microsoft supports the product with feature and security updates.
After these 5 years, mainstream support will expire and only security patches will be released.
For MS Office 2016, mainstream support will expire on October 13, 2020. This is the day on which the policy changes step in and the day all organizations using MS Office 365 services have to be transferred to MS Office 2019.