Those (Office 2013 & 365) are different editions of the same version; that is no different than any other version of Office and never has been. As for the Office 2103 vs 2016 editions of Office 265 ProPlus licenses referred to in the article, the issue here is that the article is referring to subscription licenses and, once the 'use-by' date has passed the subscription is being transferred to the Office 2016 subscription and the Office 2013 subscription license will have expired. This is thus a licensing issue rather than a technical one regarding compatibility between versions to co-exist.

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]