>Is SP4 more than a combined SP2+SP3?
>

Yes, especially since SP3 included all of SP2; you don't have to iteratively apply them. There are several bug fixes, a new CONFIG.FPW entry that aids VFP performance under Terminal Server, and a few other things as well; it's not as earth-shattering an upgrade as was SP3.

>>>If I upgrade my VFP to SP4, will this have any impact on the software that my customers are currently using that was built under SP3.
>>>
>>>Thanks
>>>Kev
>>
>>No. For your customers to get the bug fixes, you will need to ship them new runtimes.