If an installation with a lower version number is present, the new installation will be installed, and the /Versions/Current alias changed to refer to the new installation.
-If an installation with a lower version number is present, the new installation will terminate with a message - text TBD - explaining why.
+If an installation with a lower version number is present, the new installation will terminate with a message explaining why.
If an installation with the same version number as version being installed is present, a message is displayed to the User asking them to confirm whether the existing installation should be overwritten?