Renew license for PB 11.5

Hello Everyone,

Four years ago our company bought PB 11.5 and provided license files to each developers.

As you know, the license file includes such unique things as HOST ID and HARD DRIVE ID.

Now we got new computers, installed PB, but old license files can't be used.

A person who generated old licenses four years ago has left company.

How to get the new licenses ?

Thanks