FlagSync 2.4.2

is a rather mediocre program in terms of functionality, the same FreeFileSync is much more functional in terms of setting filters-exclusions (actually, I tested the program on a couple of directories, which synchronizes FreeFileSync), as well as in terms of interface (in FreeFileSync you can see at least what exactly has changed, open files, or directories containing them). So it is not suitable as a replacement.