I've just spent days locked out of my copy of Office '11.
The reason? A lapsed subscription to Office 365.
I've owned Office '11 pretty much since its release.
4-years back I subscribed to 365 as I needed it for work at the time.
When Office '16 became available I trialled it but found it was...
ONLYOFFICE Documents is a free iOS application for viewing and editing documents.
With the current version (1.3) you can
View and edit text documents (iPad/iPhone).
View and edit spreadsheets (iPad)
View pdf, presentations and other types of files
Manage all of your documents...