If you have been working with SharePoint you should know by now how to get the build version of an installation using PowerShell. Knowing the version of the installation is crucial for troubleshooting and knowing what features or limitations the current installation has, given the new release cadence. If you don’t know how to do it then Bing for it and then return here. But how do you do the same for Office Web Apps Server 2013?

Retrieve the version number of an Office Web Apps Server installation

Knowing the current version for Office Web Apps Server 2013 (WAC) is also important to know. Just as with SharePoint new features and bugs can and will be introduced over time and you need to know the version to be able to correctly get support and to patch it. Unfortunately there is not such an easy approach as with SharePoint – we cannot use the WAC cmdlets to get the current build version.

Instead we can rely on another PowerShell method – Invoke-WebRequest. Hmm, that has nothing to do with WAC you might be thinking, which is true. But Office Web Apps returns the current version as an HTTP Header – the X-OfficeVersion header.

In order to do use this cmdlet and to invoke an HTTP request we also need to send an anonymous request, to avoid 401’s. For this we can use one of the anonymous end-points that Office Web Apps Server exposes, for instance the end-point for the broadcast ping, like this:

(Invoke-WebRequest https://wac.contoso.com/m/met/participant.svc/

As you can see we request the endpoint, and retrieve the specific version header from the response. This will return the current build version of your WAC farm, for instance “15.0.4535.1000” which is the August 2013 hotfix for WAC.

Known version numbers

I have collected the known version numbers of Office Web Apps Server 2013 on this page http://www.wictorwilen.se/WACVersions. I will try to continuously update it as the WAC server retrieves new patches and upgrades. As a bonus I also added version numbers for the version that SkyDrive currently uses (interesting!).