wow you wouldn't believe this, but this is the first time in quite a while since i've been to the Vue forum and i can answer your question straight away :) I've just come from http://www.e-onsoftware.com/Order/ProductList.php?sid=8a3d6c923cc343afa913c32a13877700&l=1&producttypeid=33 And it seems yes you can upgrade from 4 to 5 i was just looking at the costing to do the same myself. David