There have been problems connected with the architecture that have been identified in migrating Sitefinity to use .Net 4.5, so until we get those issues solved Sitefinity will continue to be compiled against 4.0. Currently, our developers are working in solving these issues and we hope that we will have support for .NET 4.5 soon. For the time being, Sitefinity assemblies are compiled with .NET 4.0 and using the .NET 4.5 is not supported.
However, please note that you can install .NET framework 4.5 on your environment. Please refer to the below article for more details on this:
Recommended environment settings
You can also checkout the following forum threads where the same has been discussed:
Regarding the MVC 5 support - please note that Sitefinity officially supports MVC version 4.0
, but you can still work with MVC 5 as well, however there might be some unsupported cases which we cannot predict for the time being as the system has not been fully tested against this MVC version. Our developers are currently working on this as well and hopefully we will provide support for MVC 5 soon.
Do you want to have your say in the Sitefinity development roadmap? Do you want to know when a feature you requested is added or when a bug fixed? Explore the Telerik Sitefinity CMS Ideas&Feedback Portal
and vote to affect the priority of the items