I do almost entirely MVC applications and am running on more current OS/DB than you are. For example, we're currently moving all database servers to Windows Server 2008 R2 and SQL Server 2014. I also just added some new features to an MVC 4 application and migrated the codebase to MVC5 and more up-to-date versions of JQuery, etc.

>I got a reply
>
>That is a good question. Since we tell our client that we support any supported Microsoft OS and Server 2003 is still supported until 7/14/2015, we will need to keep it on 4.0 until next year.
>
>That being said, if there is specific functionality that is in 4.5 that would be very useful, I could discuss it with the management team to see about getting approval for requiring Server 2008.
>----------------------
>I am not sure if there is any specific functionality in 4.5 that may be a strong case for that requirement.
>
>Do you use any specific 4.5 features?
>
>-------------
>In any case, I guess for now I can keep the projects setup as is, right?