I am sorry but I failed to find any official reference about Office Online Server client license.
We have a SP2016 farm and are planning to add OOS servers. Our users have MS Office 2016 license but I heard (yes, from rumor) Office 365 license is required for OOS use.
Could you please point me to the official reference about OOS user license requirement?
Also, if only part of users (let's say 100 out of 400) have the licenses on OOS. Other users without license are readonly. Could I set the limitation on our farm?