Installing .net Framework 3.5SP1 on top of 3.0 - as simple as "install and go"?

Question

This maybe a stupid question, but as I can not easily undo my change if I decide to do it, I think i'd ask here first:

I got a Sharepoint 2007 Server. Pretty standard stuff: Windows 2003 (32-Bit), IIS 6, Sharepoint 2007, .net 3.0.

At the moment, I use Visual Studio 2005 with .net 3.0 as my target. However, I'd like to use .net 3.5SP1 Functionality because of some really nice additions.

Now, to my understanding, .net 3.0 and 3.5 are "only" .net 2.0 + some new Assemblies (greatly simplyfied), and therefore I wonder if I can just happily install the 3.5SP1 Framework on all Sharepoint Servers and use them - or is there any additional black magic needed to prevent the whole stuff from blowing up?

I assume that I will need to update to Visual Studio 2008 SP1, which is fine. Is it required to recompile any code? Can I safely reference the "old" assemblies from newly written ones? Or is there any big incompatibility that I have not found?

Answer 1

I certainly wouldn't just happily install the 3.5SP1 Framework on all [your production servers].

Use Virtual Server or VMware and build a virtual machine with your configuration, then upgrade that and test, test, test. If you think it is worth the money, there are tools that will provide a way to do P2V (Physical to Virtual) migrations so you can take your exact production configuration into a VM, rather than rebuilding it from scratch.

There are breaking changes in 3.5SP1 (see Scott Hanselman's blog for example), and if you just install without testing Murphy says you are likely to be bitten by at least one of them.