Yes, just click on Help->Updates and you will be able to update to 5.71. Just be aware that after you do that you will receive a notification telling you that there is yet a newer version which is Lightroom 6/CC. If you don't want to purchase the upgrade then just click on the ignore these notifications button in the lower left-hand corner of that screen.
Incidentally, 5.7.1 will not have the photomerge or HDR functions. Those functions and other new features are only included in Lightroom CC/6.