With SharePoint, there is a very handful tip I keep forgetting about, and that let’s you easily determine the exact build number of any given SharePoint farm. The platform exposes a Configuration Link Endpoint that let’s you get this information by simply appending /_vti_pvt/service.cnf to any web URL on your site. For example, to determine the current build version of my site (which will change frequently due to it being hosted on Office 365), you can simply access http://www.ignitesoft.ca/_vti_pvt/service.cnf. You should see something on screen that looks like the following:
This indicates that my SharePoint farm currently is running on version 18.104.22.1688 of SharePoint online.