Publishing an application in an old version of .NET

I've written a really simple launcher app for my team at work to use. However I wrote it in VB.net Express 2010 so its using .NET 4. I need it to be compatible with older machines that are using .NET 2 or maybe 2.5.

I don't want to force upgrading to a higher .net if its not needed. And in some cases we work on old machines that can't be upgraded. My app is really simple and I'll post the code if needed.

Please note, I am still a noob, my coding is ugly, and this is开发者_JS百科 a quick and dirty tool.

You're looking for the Target Framework dropdown in Project Properties.