T-Mobile is preparing to launch the latest version of their T-Mobile Jet USB modem, this one offering support for the faster HSPA+ upgrades T-Mobile has been deploying around the country. According to TmoNews and their bottomless well of leaked T-Mobile employee screenshots, the device will drop on March 23. The device will support HSPA+ downstream speeds up to 21 Mbps, though real network performance usually tends to be around half that or less depending on location. Roughly 200 million people in 100 major metro markets have access to some flavor of HSPA+ connectivity from T-Mobile, though T-Mobile hopes to have 140 million people covered in 25 major metro markets with even faster HSPA+ (up to 42 Mbps) speeds by midyear.