More than eight years after its inception in pure VB.NET, open source project DotNetNuke decided to make a leap and move its entire CMS core to the more modern and widely supported C#.

I won't revisit a broader language debate here. The difference between VB.NET and C# boils down to syntactic sugar: while syntactically they are very different languages, Microsoft made sure that both are compatible with the .NET Framework development platform. As a result, just like in case with the majority of other .NET CMS vendors – Ektron, EPiServer, Umbraco, etc. – VB.NET can still be used as the implementation code, regardless of the core product language of choice. Therefore, VB.NET should still be supported going forward in the DotNetNuke API.

So far, things look pretty peachy, but let’s move on to the shaky bits. A software core re-write is a very significant change for any platform. The TCL-to-Java conversion caused years of pain for (then) Vignette that scarred the company indelibly.

If you're using DNN, the good news is that the weight of this huge task doesn't fall on your shoulders -- at least not immediately. Most of the work of converting the core to C# was done by a DNN enthusiast developer in China, Ben Zhong. Instead of forking (too much overhead), DNN Corporation decided to accept Zhong's codebase as the basis for a complete conversion. The new codebase currently remains in QA, with a planned release as DotNetNuke 6.0 in Q2 2011.

The not-so-good news here for DNN-based sites is that your VB developers -- and it's still not uncommon to see developers use VB -- will have to start putting their old tricks to rest and learn some new ones. More importantly, DotNetNuke is notorious for cutting corners around testing new releases. You should tread the muddy upgrade waters cautiously.

This move further manifests DotNetNuke's aspirations to be taken more seriously for enterprise-scale .NET WCM deployments (a déjà vu moment), but wholesale rewrites are tricky and can bring longlasting consequences.  So for customers there's still a long, winding road ahead.