I am currently looking at the 5306C variance of this phone. It supports HSDPA 850 / 900 / 1900 / 2100, and LTE 850 / 1700 / 1900 / 2100.
Based on the specs, it looks like this phone supports AT&T's 3G HSPA and LTE frequencies. It also supports T-Mobile's LTE network but bizarrely missed the...