T-Mobile has announced a software update for its version of the Galaxy S5 that, while nothing exciting, should address an issue some customers have experienced. The change log contains a single item, an improvement that alleviates occasional incoming SMS/MMS failure. Following the update, the S5 should receive messages more reliably, assuming it hasn't worked fine for you thus far. The version number is G900TUVU1ANE5.
The update is 131MB large and is available as an OTA or via Samsung Kies.