SharePoint 2013

Central Administration à Upgrade and Migration à Check Product and patch installation status

Office Web Apps

Open PowerShell as Administrator on Office Web Apps Server

(Invoke-WebRequest http://officewebapps.com/m/met/participant.svc/jsonAnonymous/BroadcastPing).Headers[“X-OfficeVersion“]

For Version Comparison

SharePoint 2013 Build Numbers by Todd Klindt