After RM-914 and RM-915 the third variant of Lumia 52o, the RM-917 aka T-Mobile bound Lumia 521 has passed through  FCC. If you remember T-Mobile has already announced Lumia 521 coming to the carrier but did not mentioned any timing or price at which it will be launched. But if an earlier leaked screenshot is some indication then it is supposed to be launched on 24th of April.


Surprisingly Bluetooth and WiFi certifications also mention RM-915 coming to North and South America so may be that also comes to some other carrier, probably AT&T as it supports AT&T specific frequencies.



FCC link