It is just about 3 month that I bought an ultimaker 2+ 3D printer, but now I realize that I had to wait.
I already asked to ultimaker whether they have an update to my printer and the answer was this:
Sorry! we won't be able to offer an upgrade kit for the Ultimaker 2 series, as too many parts have been changed between the two models.
How reliable would to add a dual extrusion with ulticretr http://ulti.creatr.it/en/index.html ? Can I invest $500 us for this? what about the price of water soluble PVA?