>Can you tell us what you mean by backend is VFP ? Is it only the storage (dbf) or even some business logic. I have read some members say that one of the advantage of VFP is lost after SQL Express storage limit has been increased.

Backend means the storage. Yes, this is Visual FoxPro. I don't know what you mean by the last line. Could you elaborate more on the topic?

>Currently were are using FPD 2.6. Do you have any suggestions ?

If you are about to release a new version then you should seriously consider moving it to OOP. Isolate the data engine in a class so if you change the backend at any time, this should be limited amount of changes to apply.