I decided to test the 3.0.0a1 with Servoy 3.5.9 in case it could solve
a problem that I had and I wanted to see if it could work.
I am NOT using the foundset capabilities I only want to test if it is
compatible with the reports that I already have under Servoy 3.5.9 and
with using reports created by iReport 3.5.2 (that is these reports
need the jasperreports-3.5.2.jar engine to work).

Here are my results:

1. I had to include the itext-2.1.0.jar in the jnlp file otherwise I
could not get any file to be saved in any out put format such as pdf.
2. All my reports render fine in the Smart Client on the Jasper
Viewer. From this viewer I can then select save as and select the file
type.
Saving the viewer file to one of the selected output format works for
all type EXCEPT the XLS (excel) types.
3. If I use my Servoy application and send the plugin the output file
format I desire as well as the file pathname then NOTHING gets output.
Perhaps there is a different parameter order than the plugin version
2.1.5 (I did not change any of my servoy code to do this test). I will
check on the parameter order in my next test round.

So I think that there might have to be a little rewording of the
prerequisites of the Servoy version for this plugin - if it works for
my 3.5.9 application perhaps it can be used for others who want to use
the iReport 3.5.2 but like me found it does not work with the servoy
plugin 2.1.5

I hope this is encouraging.