When installing the application on my X6, it comes up and says that the phone is not compatible. I did download the correct version and even went back and checked again, just in case.
I still installed the app and it seems to be working fine, apart from there is no Change Language option, but I don't have another language dictionary in the phone, so this could be why.
X6-16gb
S60 5th Edition
v21.0.004 (Custom Version 249.09)