Sorry, I had to delete this link - for several reasons:
We don't know this software - can be a virus too
If it's Fuji firmware, we don't know what status it has (final / beta / alpha)
Depending on the status a buggy firmware can harm your hardware too
Having said this: If you want to take this risk, feel free to go to the Fujistas
http://fujistas.com/foro/x-t1/ya-disponible-firmware-4-0!!!!/
Sorry to be a spoil-sport - but your security is important to us...
