I just tried the firmware upgrade feature. It tells you which version of software you have and then downloads the latest firmware version. You likely have version 1.6 of the software, and now have version 1.5 of the firmware.
Which brings up another point, I downloaded the latest software and firmware, but still only see:
Version: Software 1.5 Board 0.1 (0x01:0x4c)
Is it possible that the newly-purchased remotes have a version of the software that is more recent than that available on the website?