upgrade via rpm erase the product

Hello everybody,

Like the company installation policy has changed, we must use rpm package to
install JOnAS (before we used the tar.gz version).
I have tested the installation of the stable Jonas 5.2.0 version with rpm -i
command. This installation works. 
But when I upgrade this version with last Jonas 5.3.0-M2 version with rpm -Uvh
or rpm -F command, the installation is completed without error but the
/opt/jonas directory is empty.
The post uninstall script of the jonas 5.2.0 rpm has a rm -Rf /opt/jonas/*
command, I think it the reason of the erasing.

I am not a system administrator and I have not used with package life cycle.
Perhaps we must do a remove (rpm -e) before upgrade?

Best regards,