Does this mean that your T-Mobile SpringBoard has just gotten a new lease of life? I guess you can say so, as in the changelog provided by T-Mobile as you can see in the link, it will boast of an improved touch experience which in all probability would be more responsive, doing away with the bug that involves an unrecognized SIM card error, in addition to improved Wi-Fi signal reception. The update itself will also be able to help your SpringBoard improve memory allocation so that it is capable of receiving future operating system updates, now how about that?
Just make sure your T-Mobile SpringBoard has at least 50% of its battery life before you install the OTA (Over The Air) update, otherwise you will never go wrong by leaving it plugged to a power outlet throughout the process. It goes without saying that a Wi-Fi connection comes across as highly recommended, in addition to having at least 90MB of space available.