I just received this from Humminbird:
Thank you for contacting Humminbird. We appreciate your interest in our products. I do apologize for the late reply. Was speaking to our service technicians on this. There was a glitch with the software programming that this feature was not included on the software release 7.790. Unfortunately, there will be no software release after this current version due to the fact the unit themselves are no longer manufactured.
FYI, they are referring to the 8XXci, 9XXci, 11XXci models.