The current situation is roughly:

  1. The majority of PCs have a version of the .NET Framework
  2. A fair number of PCs do not have the .NET Framework
  3. A fair number of PCs have .NET Framework 1.1
  4. A lot more PCs have .NET Framework 2.0
  5. A lot of PCs have .NET Framework 3.0
  6. In comparison, relatively few (bare in mind this is still a lot!) have .NET Framework 3.5
  7. In comparison, relatively few (ditto) have .NET Framework 3.5 SP1

As a developer writing .NET Framework applications this poses a challenge. Which Framework version can you target, especially if your application is expected to be widely used across organisations and/or households? Right now the safest option and best “compromise” is to target the .NET Framework 2.0 if you want the broadest reach with the least “hassle” for your users. However, .NET 3.5 SP1 gives you so much more in your “toolbox” to build a great application that your users will adore. We are very aware of the difficulties this poses and hence we have a “cunning plan”.

The cunning plan:

We will be making .NET Framework 3.5 SP1 available on Windows Update in a rolling and throttled fashion. This will mean that all machines that have .NET 2.0 or higher will be automatically* upgraded to 3.5 SP1. Before we do this there will be a patch called a General Distribution Release (GDR) for .NET 3.5 SP1. This GDR will fix bugs that have been found in .NET 3.5 SP1 since its release in August. Scott has done a great job of covering this off in more detail back in September, including a detailed breakdown of the fixes in the GDR. Scott mentioned this will start in November but I think it may take a little while longer whilst we ensure we have a great GDR for SP1.

* This upgrade won’t quite be automatic. First up, your users must be using Window Update. If they are on Windows XP then the update will be ‘High priority’ and on Vista it will be classed as ‘Important’. For customers that have Automatic Update opted in, this means SP1 will be automatically downloaded and installed. In effect this means most users.

P.S. And remember, for PCs with no .NET Framework we have the .NET Client Profile. Scott has a good summary of the .NET Client Profile and .NET install sizes in general. (Actually I think Scott has a good summary of everything!)