>a developer has VFP 5.0A
>he builds a .app file...
>a user has the VFP 7 runtime library installed on their machine.
>According to 'official Microsoft documentation' will the user with the VFP7 runtime library installed be able to properly run the VFP 5.0A built .app? Are there 'small problems' which MS won't take responsibility for supporting?

Problems might arise and some are depicted in readme.htm + docs. ie: parameters cannot not be separated by blanks, SQL results might be different...
Cetin