Qvd's can be used in Qlik Sense. Qvd's created by Qlik Sense have a new data format and cannot be used in Qlikview for now. Qvd's generated by Qlikview can be used in Qlik Sense.
Qlik sense applications are saved with a qvf extension.
Couple extra things.
In QVF (Sense) the data connections are stored separately to the script and in a server environment become a governable resource.
Also in the QVF, the images are completely externalized to a content repository that stores the images externally. The content repository must follow the QVF file to different desktops or to the server to render correctly. This is not the case in QLkView. The benefit is that in a server based environment the content repository is a securable resource giving developers access to the same images.
I add some more here QVF file can be store in APPS folder which is located on this location.
This may wary from system to system but need to keep the QVF extension qliksense file on APPS folder and the connection name is used for Data source location should be properly used on the Qliksense Server also. The Qvd created in Qliksense is not readable on the qlikview application but qvd created on the qlikview can be readed on the qliksense.
Thanks & Best Regards