X-AspNet-Version header is exposed, its value reflects actual .NET version of the Office 365 Application Endpoint.
This header is exposed by default.
Feature Request #PFR-1254: "Office 365: Hide the 'X-AspNet-Version' response header on the Endpoint side" has been addressed to Odin Development team in order to implement such functionality.
Add the following setting to the
system.web section of the
<httpRuntime enableVersionHeader="false" />
and restart the IIS service.