I can answer the question from both a professional (I am an electronic engineer) and a practical point of view
(The governmants digiatl TV website covers most of this in some detail)
Most strata rsidents by now are receiveing difgatal TV. If you can receive channels 72,73, 90, 99 etc then you are reeiving digital. (this sort of assumes that people have a digital receiver of some sort, but by now most people do) In this case there is no need to do anything when analog is switched off. This again is on the assumption that a common antenna is used for most units.
If you can’t receive any or some digital channels, it indicates that the signal at the lot is not sufficient. In this case it’s necessary to get an antenna expert in to diagnose the problem and upgrade.
There are antenna labelled digital ready, but the only real difference is that they are smaller than an analog antenna as they do not have to receive analog channels 2 and 0. the old analog antenna will wotk just fine on digital signals.
In my strata, we had poor reception on some digital channels even though we were in a high strength signal area. The antenna’s were 35 years old, so we replaced them (only) and the problem was solved. It was a few hundred dollars only.
Most older starta could do with a replacement of an old antenna, so we just chnaged out ours under maintenance.
Robert