Hi Aviad,
Did you ported your Application to 7.31 or you
just used the PAR migration tool?
If you only used the PAR migration tool it is
very likely that the application will not work.
From 7.0 to 7.3 onwards, there were huge
changes on the Portal and many libraries were removed/changed causing 7.0
applications not to run on 7.3.
Please check the link below on how to port the 7.0
applications to 7.3.
Best regards,
Cristiano L. Mazzotti