You already have a serial number for the downloadable version? Download it from here!" Remember that each licence (i.e. each serial number) gives you the right to three software activations

SOFWTARE UPGRADE
Our downloadable software is always up-to-date with the latest changes made to all operative systems by their producers.
Whenever you experience a malfunction after a sensible upgrade of your OS, you can at any time download the latest version of our software.
Before installing the latest version, you must always deinstall the previous version. Remember to deactivate the product before deinstalling it, in order to keep all your activation chances.

64-BIT MAC UPGRADE
If you upgraded to Lion (OS X 10.7), to Mountain Lion (OS X 10.8), or to Mavericks (OS X 10.9) and you run a dictionary purchased before January 2013, you can download and install for free the Mac OsX 64 bit version of the software.
As usual, remember to deactivate and deinstall the previous version before.
In case of problems with Mac 64 bits and Java, read here.