The SewArt64 is the 64bit of the application that was designed to work exclusively on this architecture type. However, I've seen that the version 1.5 was one of the released ones on the official website as well. There is nowhere on the developer's website mentioned about the system requirements, but I've downloaded the product and installed it on Windows 10 64bit and it simply works.
This was probably a matter of choice as the latest version can be installed on both architecture types.
