Online voting/app would certainly get my vote (Pun intended) and be an improvement and can't see any issues with our government pushing for that, although it would need to be staged such that the older methods are removed over time..
However, saying all that, this entire subject has only come up because some cry babies can't accept the outcome of the last couple of GE's and are just salty/acting all entitled..
The retired population has always been there, and who knows, in the next GE or one after that they may well align with the younger vote again.
The issue with crying about it unnecessarily is it's quite easy to start an argument for making any demographic less relevant, but that's not conducive to democracy now is it..
You also know that whilst now the whiners feel a digital vote method would favour them and are already saying how the evil tories won't let this happen would be the very first to claim voter fraud themselves if future 'digital' elections didn't go their way and start pulling up skewed stats to try to marginalise entire demographic groups that they can 'blame' for the incorrect outcome..