Microsoft now has multiple Office 201x install and update policies covering both Office 2016 and Office 2019. At this time, there is no difference in the kinds of files produced by the different versions of the apps. A spreadsheet made in Excel 2019 should work fine in Excel 2016 and vice-a-versa. The difference between the versions comes down to which OSes are supported, licensing and feature set. Office 2019 is getting new features and Office 2016 is stuck in amber and will only get security updates for another couple of years. Things to note:
- Can support any macOS between 10.10 to 10.14
- Is any version of Office that is version 15.x through 16.16.x.
- From this point on, Office 2016 will remain version 16.16.x. As security updates are released each month, it will increment like so: 16.16.3, 16.16.4, 16.16.5 and so on.
- Office 2019 has a minimum OS requirement of 10.12, and this requirement will change when the next version of macOS is released, i.e. when 10.15 is launched 10.12 support will be dropped and 10.13 will become the new minimum supported OS.
- Is any version of Office with a version higher than 16.17
Editor's Note: Whoever at Microsoft thought it would be a good idea to have Office 2016 span versions 15 and 16 and have Office 2019 share version 16 with Office 2016 needs to step outside the office, talk with a few IT managers and experience the repercussions of that decision. Boo. Hiss.