I finally found a second to install VS2010 and .NET 4 RTM on my laptop and I must say it’s looking good. Needless to say, the first thing I did was to open one of my EPiServer CMS 6 projects, imported it, changed the framework to .NET 4 and tried to run it in the Visual Studio web-server. At first it looked good, but when I tried to reach edit/admin mode I was greeted with 404 errors.

After looking through this list of ASP.NET 4 breaking changes I figured I might want to try to play around with some web.config settings.

In the <location path="EPiServer"> section I made the following changes:

• I added requestValidationMode="2.0" to the httpRuntime tag and
• I set validateRequest="false" in the pages tag.

Then I could easily browse shell, edit and admin mode as well as edit and publish pages.

NOTE: I did not do a full test of the functionality – and with the impressive list of breaking changes in ASP.NET 4 I wouldn’t be surprised if there’s something I missed. If you know of other things that needs to be changed, feel free to leave a comment here. And use this as your own risk.

When all that is said and done, it seems like there’s a lot of interesting stuff in ASP.NET 4 – can’t wait to play around with it! http://www.asp.net/learn/whitepapers/aspnet4.

P.S. My first impressions indicate that EPiServer CMS 5 R2 seems to work as well running together with .NET 4.