Hi,

No you don't need to change the business layer to .NET 4. You should not be modifying the mojoPortal code and it works fine under .NET 4 and also supports .NET 3.5. We have separate presentation layer projects so that we can still support .NET 3.5 installations but we don't need to maintain multiple projects for the business nor data layers because the 3.5 versions are compatible with .NET 4.

If you are doing custom development your code should be in your own projects where you have the freedom to do what you want.

Joe

I don't recommend making any changes at all to mojoPortal code.

Your reason doesn't really make sense to me because even if you are trying to reference our business layer from another project or assembly that is implemented in .NET 4 you still do not need our assembly to be a .NET 4 assembly. You should never add any custom code into our projects. 

If you make that change you will never be able to upgrade to new releases of mojoPortal other than by producing your own build from source code, you will never be able to upgrade using our release packages (at least until we drop support for  .NET 3.5 and that will probably be quite a while yet).

My advice is don't do it.

Its not going to break anything except for compatibility with .NET 3.5 if you change the target framework.

However I still recommend against it for reasons given and I don't really see a need for you to do that, it should not be needed to do that in order to integrate with other libraries.