Short answer, I lift the keg and update the database. I'm re-vamping the Kegerface source code (the original, not the Hymaswood branch) and will be trying to add automatic updating.
The original only had SRM 0-40 in increments of 5 (0, 5, 10, etc).
The SRM colors were wrong.
The was no SRM numerical readout.
He only had bitterness in 0 - 3 hop icons.
There was no IBU numerical readout.
There was no tasting notes section.
I'm still working on the Alcohol column and Status columns. I'll be adding a shotglass scale for the ABV, like in the two left columns. Right now, the status column looks like it's a battery meter, with only 5 states (0%, 25%, 50%, 75%, 100%). I say battery meter because it goes from 100% fully green to 0% red outline like a cell phone display. I'll be re-working that to look like a keg as well.
Just bought 10 flow meters today, so hopefully I can rig up real-time updates. I'd also like to make RFID drinker cards and accounts ala Kegbot as well. Last, I'd like to install solenoids in the lines to prevent accidental spillage.
More info:
https://www.homebrewtalk.com/f51/feeler-any-interest-digital-tap-lists-450400/#post5778120