Office 365 sub required for Windows 10 Mobile on Lumia?

[MrKappa]

I hope this is the right section for this question but since few days on my Lumia 720 with last Insider Preview and of course all updated apps (Office etc) I see that I cannot edit any word, excel or ppt document because I should require Office 365 subscription.
As I understood from the news Office should be free for small devices and it should be a wrong strategy pushing people to other OS as android, iOS etc.
Also I don't see any alternative office application (except if I install android apk) available on the Windows store.
Is it definetively this Ms strategy?
I may return to Win 8.1 which is good as phone but lacking some important features and I don't know if now there is the same situation.

 

[MrKappa]

I have checked today and I see that Office 365 requirement notification appear if I open the office document from Outlook but if I save the document first on the SD card I can edit later without problem. So it seems to be fine for the moment.