Is there way to reduce viewer.xap size?

[SteveLi]

by using technique such as Application Library Caching?

[PietaSwanepoel2]

Make a backup of viewer.xap

Open the viewer.xap file in program like 7-zip. Delete the dll's that would not be required and save it

All this assumes that the dll's that were removed from the xap file are installed on every client machine, else it will fail