Oracle has released an updated version of their Swiss army knife add-in for MS Office. The installer for Oracle Smart View 126.96.36.199.215 is currently only available in form of a patch on Oracle Support (Patch 18977986: Patch Set Update: 188.8.131.52.215 for Oracle Smart View for Office) but I expect the Smart View page on OTN also to be updated soon.
As of this version Smart View is certified with Windows 8.1. Most of the other changes are bug fixes to make the add-in work more smoothly with Oracle BI products but a handful of other issues have been addressed as well. As always, have a look at the readme file on Oracle Support to get the full details. Also note that two server-side patches are required in order to get full benefits of the fixes related to OBIEE.
Update: Oracle has now released a knowledge base document on My Oracle Support to clarify supported OS and Office versions and interoperability between Smart View and other Oracle products: