Multiple platform version releases of Sitefinity
In Sitefinity v. 3.7 SP4, there was a release version for .NET 3.5 and .NET 4.0. That was especially useful since you could then use whichever version of Sitefinity that supported the framework you were running.
However, with every release of Sitefinity since v. 4.x, there is no .NET 4.0 AND .NET 4.5 release.
This is quite problematic because development cannot leverage the new features in the Telerik .NET 4.5 assemblies and are instead stuck with the .NET 4.0 assemblies.
As with the Sitefinity v. 3.7 SP4, release, Telerik should release versions of Sitefinity that support .NET v. 4.0 AND .NET v. 4.5, rather than just the single platform of .NET v. 4.0 which is simply TOO restrictive.
Currently, Sitefinity assemblies are compiled with .NET 4.0 and changing the target to .NET 4.5 is not supported. I am not able to give you a time frame when we will introduce support for .NET 4.5.
However, you can install .NET framework 4.5 on your environment in order to take advantage of the features of this version. You may refer to the following article for more details on this.
There is VERY little diff from 4-4.5-4.5.1
I have all my sites on 4.5.1 with no issues
Yes, I was able to get my site running on .NET v. 4.5, but I noticed that the Telerik Web UI assemblies do not behave the same way from v. 4.0 to v. 4.5.
For example, Model Binding IS available with the .NET v. 4.5 Telerik Web UI assemblies and is automatically used when creating controls such as the RadGrid, however, when you attempt to use this capability in the RadControls that ship with Sitefinity (still v. 4.0), you do not have the features and capabilities available.
Therefore, it is DEFINITELY useful to have a .NET v. 4.5 version of Sitefinity that ships with the native .NET 4.5 Telerik RadControls rather than being confined to simply the .NET v. 4.0 assemblies.