Can I upgrade from V7 to v10?  or do i need to instal a full version of v10?

If you are upgrading to Pervasive PSQL v10 from an unsupported version, you must uninstall the old version before you install Pervasive PSQL v10.

 PSQL v8 or PSQL v9 will be archived, but for earlier versions, you have to uninstall.

 When purchasing the license, however, there *IS* a small discount for users of old legacy code (including PSQL7) that amounts to a 10% discount for the same quantity of users.   If you need to increase the user count at the same time, though, then consider purchasing a full license instead, which will likely be cheaper.