A version update for the RICOH THETA app was released on September 25, 2017.
Contents of the version updates for each of the RICOH THETA apps are as follows.
RICOH THETA S
・4K video can now be transmitted without any resizing on devices with iOS 11.（iPhone7～）
- iOS11 device installed the version 1.13.3 is not able to post still photos and movies directly on Facebook. (Currently in progress of its compatibility.)
Official announcement is here.
Update: I got this on Twitter. Can someone confirm this?
Update from Facebook.
Richard Stark said: “Works a lot better with iOS 11 now, still a few bugs here and there”