What version of the .NET framework do you recommend for mass use?

Basically, my program does not install, as it is dire that there are no external dependencies, so there is no way to install frameworks if the consumer does not have .NET 4.x. I only have experience working with version 4.0 so I'm not sure if it would be detrimental to downgrade to, say, version 2.0 for the sake of supporting older systems. My program establishes network connections and installs proprietary hardware hooks. Will v2.0 support this just as well as v4.0?

Short answer: "Probably". Longer answer: "Probably, but test it first."

A slightly longer answer: "It's pretty much all built on top of 2.0 (which might be somewhat less true for the upcoming version), so - probably, with some extra work; but test it first."

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