Vmware View and Vmware Horizon are the same thing. It was the transition of renaming the product from View to Horizon.
Thinapp still works with the newest versions. An "alternative" method is deploying applications app volumes. App Volumes and Thinapp aren't an apple for apples transition and different based on what type of deploying of apps you are after.
As for the upgrade, follow the link sjesse provided. My opinion is to run the build.bat instead of relink.exe ot upgrade the package to ensure there isn't any incompatibility between version upgrades.