There is a (non-Microsoft) NuGet package that allows upgrading the Mvc3 to Mvc4. There is a (Microsoft) article that explains how to manually migrate from Mvc3
armadillo
routing
aws-cdk-context
mineflayer
clp
grxml
kiwi
cordova-ios
google-optimize
vaadin7
flexdashboard
ilogger
busy-waiting
excel-template
typesetting
ms-office-script
git-clean
centralized
asyncdisplaykit
mod
libmysql
php-mssql
wso2-apim
git-sync
image-rs
xamarin-shell
fakeredis
correspondence-analysis
css-parsing
tkinter-label