>I am installing my app on customer server (Server 2008). I see that their server does not have .NET 4.? installed. So I need to download a redistributable from MS site. On my development computer this program is running under .NET 4.0.30319 (this is the ver I see in c:\windows\microsoft.net\framework). I find online both .NET Framework 4.0 and 4.5 redistributable online. Which should I download and install? TIA

The .NET 4.5 install should be an in-place replacement for the .NET 4.0 files. See the 5th bullet point under important notes at http://msdn.microsoft.com/en-us/library/ee942965.aspx. There are also some more references at http://stackoverflow.com/questions/15113873/does-net-4-5-include-net-4-0.