Updated. Back in September T-Mobile CTO Neville Ray promised that “a material” portion of T-Mo’s HSPA+ network would be able to support the iPhone by the end of the year. He wasn’t exaggerating. T-Mobile revealed on Thursday it has completed its iPhone-friendly network overall in 14 more cities, including New York, Philadelphia, Boston, Dallas and Detroit.

Coupled with the markets T-Mobile has already upgraded, it has a new HSPA+ network running in the PCS 1900 MHz in 37 cities, including many of the country’s largest. T-Mobile isn’t updating its coverage figure for the overhauled network, but these new markets will add considerable numbers to its last count of 100 million people covered.

T-Mobile will begin selling the iPhone sometime next year, but in the interim it has been trying to lure customers with unlocked iPhones over to its network. Its biggest obstacle, however, was the fact that its old network configuration could only supply the iPhone with 2G speeds. By relocating its HSPA+ from the Advanced Wireless Service (AWS) to the PCS band, it can now link to the iPhone’s 3G radios, but T-Mobile also clears up space for its LTE launch next year.

Update: Interestingly enough, T-Mobile customers won’t be the only ones benefiting from this upgrade. T-Mobile mobile virtual network operator Solavei said it would take advantage of its wholesaler’s reconfigured network to support the iPhone as well. Like T-Mobile it won’t sell the iPhone, but it will sell a micro or nano-SIM that fits into an unlocked iPhone and allows customers to take advantage of its $49 unlimited voice, text and data plans. Other MVNOs like Straight Talk already offer similar iPhone SIM activations, though they work mainly on AT&T’s HSPA network. Now that the reconfiguration is well underway, expect more MVNOs to start offering iPhone support over the T-Mobile network soon.

Here is the full description of the new upgraded markets from T-Mobile’s blog:

• New York, including The Bronx, Brooklyn, Manhattan, Queens and Staten Island
• Newark, N.J., including the surrounding cities of East Orange, Elizabeth, Jersey City, North Bergen, Paterson and Union City
• Boston and Cambridge, Mass., including the surrounding cities of Amherst, Andover, Arlington, Bedford, Belmont, Billerica, Braintree, Brockton, Brookline, Burlington, Canton, Chelmsford, Chelsea, Chicopee, Dedham, Everett, Framingham, Hadley, Holbrook, Holyoke, Lawrence, Lexington, Lowell, Ludlow, Lynn, Malden, Marblehead, Medford, Melrose, Metheun, Milton, Nahant, Natick, Needham, Newton, Quincy, Reading, Revere, Salem, Saugus, Sommerville, Stoneham, Swampscott, Tewksbury, Wakefield, Walpole, Waltham, Watertown, Weston, Westwood, Weymouth, Wilmington, Winchester, Winthrop and Woburn
• Springfield, Mass.
• Providence, R.I., including the surrounding cities of Cranston, North Providence, Pawtucket and Warren
• Philadelphia
• Detroit and Warren, Mich., including the surrounding cities of Dearborn, Romulus, Royal Oak, Sterling Heights and Troy
• Dallas, including the surrounding cities of Arlington, Carrolton, The Colony, Denton, Farmers Branch, Flower Mound, Frisco, Garland, Grand Prairie, Irving, Lancaster, Lewisville, McKinney, Mesquite, Plano, Richardson, Rowlett and Southlake
• Fort Worth, Texas, including the surrounding cities of Keller and Mansfield
• Austin, Texas including the surrounding city of Round Rock
• San Antonio
• Tampa, Fla., including the surrounding cities of Clearwater, Largo, Safety Harbor, St. Petersburg and Vinoy Park