I’ve written before about installing .NET Framework 1.1 and 2.0 side by side (SxS) on the same box.  Microsoft recently added to the mix .NET Framework 3.0, so it’s about time to clear up any confusion on the newest release.

Above all, you should understand that the version designation of 3.0 was strictly marketing-driven.  At the most basic level, .NET Framework 3.0 equals .NET Framework 2.0 plus a bunch of new DLLs.  If you install .NET Framework 3.0 on a box that does not already have .NET Framework 2.0, the installer installs Framework 2.0.  Therefore, if you already have .NET Framework 2.0 installed on a box, you should not be too concerned that installing 3.0 will break existing applications.  In fact, you will find that in the ASP.NET tab in IIS Admin, .NET 3.0 is not even a choice.

It is worth noting that .NET Framework 3.0 is pre-installed on Windows Vista and will be pre-installed on “Longhorn” Server.  However, .NET 3.0 may be installed on any Windows XP SP2 or Windows Server 2003 SP1 box.

If you’re working with a mission-critical server then you should, of course, be cautious and do some planning and testing anyway.  Just be aware that the 1.1 to 2.0 story is identical to the 1.1 to 3.0 story, because 3.0 is in effect 2.0 with more files.

By now you may be asking what .NET Framework 3.0 is good for if it is essentially Framework 2.0.  .NET 3.0 delivers a number of long-anticipated and important features, though mostly of interest to application developers rather than server administrators.  The list includes Windows Communication Foundation, Windows Workflow Foundation, Windows Presentation Foundation and Windows CardSpace.  You can read more about them on the official .NET Framework 3.0 site.

In summary:

  • .NET 3.0 is not a major change to the core .NET Framework as was 1.0/1.1 to 2.0
  • If you currently have only .NET Framework 1.0 or 1.1 and you are looking to install 2.0 or 3.0, see my side-by-side post
  • If you currently have .NET Framework 2.0, installing .NET Framework 3.0 is not a major change as the version numbers would suggest
  • If you currently run .NET 2.0 applications, they will not know or care that you have installed .NET 3.0

Please feel free to contact me with questions and your own experiences with the upgrade.  Thanks for reading!