The Tracker4 can be updated from a PC (not a Mac) using a Mini-B USB cable and the " Tracker Software Updater" software. The software leaves a lot to be desired (i.e., cryptic messages, a separate installation to install drivers, etc), but it works.
(As of the Fall of 2020, the Updater only supports the Tracker3. It could be downloaded from this Google Drive.)
The T3 Utility Software will also perform a self test and generate a self-test report.
To determine which version of software is in your Tracker4:
The Tracker4 was released with version 6.4.