These 10 additional regions bring T-Mobile's 1900MHz HSPA+ footprint to 15 markets including the previously announced markets of Baltimore; Houston; Kansas City; Las Vegas and Washington D.C.
T-Mobile CTO Neville Ray announced the upgrades in a company blog post. Ray also added that the company is working on "network advancements" in Boston, Chicago, Los Angeles, Minneapolis, the New York metro area, Philadelphia, San Diego and Seattle.
It's unclear if that means HSPA+ in the 1900MHz spectrum, but it probably does. Meanwhile, The deployment of 1900MHz HSPA+ allows T-Mobile to provide faster speeds to unlocked iPhones, but also to support other AT&T devices -- asides from just iPhones -- at HSPA+ speed.
HSPA+ isn't really 4G, but it's the best T-Mobile USA currently has. In the past, before it rolled out LTE, AT&T called its own HSPA+ service 4G, as well. Most tech analysts call HSPA+ faux 4G, though.
Meanwhile, the company plans to move to LTE and true 4G in 2013. That will just be a launch however, and T-Mobile is far behind the other Big Four carriers (Verizon, with the biggest LTE network; AT&T, and Sprint, just beginning LTE service) in rolling out true 4G.