Answer: You can always install a new build of Foxhound on top of an old one, and your data will be copied and upgraded.

However, in some cases you may be required to provide a new registration key after the data upgrade and installation is complete:

• A new Evaluation build can be installed on top of an old Evaluation build without providing a registration key.

  A new Evaluation build will not change the expiry date.

  Only one Evaluation period is allowed per customer.

• A new Basic build can be installed on top of an old Basic build, and a new Extended build can be installed on top of an old Extended build, without providing a registration key, until the "free upgrade" period ends.

  The end of the current free upgrade period has not been announced. When such an announcement is made, you may be able to use your "Original Full Build Number" to determine if you need a new registration key.

  Your Original Full Build Number is shown on the About page.

• An Evaluation copy may be upgraded to Basic or Extended, and a Basic copy may be upgraded to Extended, at any time by providing a registration key on the About page. This process does not require you to install a new build.

See also...
How do I get a copy of Foxhound?
What are the differences among the different editions of Foxhound: Evaluation, Basic and Extended?
How do I install Foxhound?
How do I restore the old build of Foxhound after installing a new build?