The razor Web.config sections added by ServiceStack.Razor normally use the version of ASP.NET WebPages that's installed on your computer included with VS.NET installation and updates and is normally located under:
C:\Program Files (x86)\Microsoft ASP.NET\ASP.NET Web Pages\
This holds the different version of ASP.NET Web pages installed, e.g:
v1.0\
v2.0\
Another option for installing ASP.NET WebPages is via NuGet, i.e:
PM> Install-Package Microsoft.AspNet.WebPages
This will install the latest version of WebPages which is currently at v3.1.1 and means you would need to change the version number in the Web.config to Version=3.0.0.0.
You can install the specific 1.0.0.0 version of ASP.NET Web pages with:
PM> Install-Package Microsoft.AspNet.WebPages -Version 1.0.20105.408
Only configuration section used
ServiceStack doesn't use the WebPages implementation itself, the configuration is primarily included to keep VS.NET intelli-sense happy as well as providing a way to configure the default namespaces added to Razor pages.
Although this can also be done in code by adding to the Config.RazorNamespaces
collection, but adding them to the config section lets VS.NET knows about them so you can get proper intell-sense, otherwise it doesn't have any effect on the execution of the pages at runtime.