As of today, T-Mobile customers in 55 markets will have access to an increased 4G network speed, which promises theoretical peak download speeds of 42 megabites per second (Mbps).
Now, this is a big bold claim and we hope the truth lives up to the hype. Surely, you remember AT&T's LTE demo, which failed to reach the promised download speeds of 100 Mbps by about 70 Mbps.
Currently, HSPA+ achieves download speeds of around 21 Mbps. Although you'll need new phones and modems to take advantage of the full speeds of HSPA +42, older, slower devices should also get faster. That's because part of the HSPA+ 42 upgrade is to upgrade the backhaul connections to T-Mobile's cell towers, which benefits all of their devices.
With the AT&T buyout looming on the horizon, the future of T-Mobile's entire HSPA system is anyone's guess. When AT&T announced its intention to aquire T-Mobile, it said it would eventually turn off T-Mobile's HSPA+ network to use the airwaves for LTE. T-Mobile can't guarantee that its network will remain intact if the merger goes through.