This is the bit I don't understand.
Because VM have said so! - i.e. that they are terminating the transmission of all analog (TV and radio) signals on the cable - i.e. the signals that more or less date back to the NTL/Cablelink/Communal Aerial days and that could be tuned in using just a TV or radio (and no need for any digibox decoder because the signals were analog and not digital).
Once that is done the only way to get access to any content on their cable will be using a digibox which will decode the digital signals that carry TV and radio channels (including radio channels that might be analog - e.g. FM - in their original broadcast format but carried in digital form on the VM cable).
And it frees up extra space for more digital signals (e.g. extra TV/radio channels, more broadband bandwidth).
I am assuming that they are not changing their digital signals at all and so will continue to carry the same digital channels and radio.
But, honestly, THEY should be able to tell you without you needing to depend on third party forums like this!
The only people affected will be those who still use the "old" analog signal via a TV or radio (without a digibox) - that means me (fair enough since I haven't been paying them for this in years
) and you if you have multiple TV/radio points in your house only one of which is via the digibox with the others connected directly to a TV or radio.
I'm sure that VM will provide you with additional digiboxes for your other rooms - and charge you for the privilege...
Edit: actually I see now that VM are not as explicit as I assumed about switching of ALL analog signals:
https://www.virginmedia.ie/switchoff/
But when they say "analog TV" here I presume that they actually mean all analog signals (TV AND radio). But again THEY really should be able to explain what they are doing to customers....