Upgradeable ticket types

Hello all a quick question I am thinking of taking advantage of VS special PE fares at the moment, mainly for a mileage run and a weekend away, my question is will these tickets be upgradeable with cash on the day as I know only certain types are available to upgrade ?

Thanks

[Decker]

At the airport all bets are off - if people are prepared to pay enough for the upgrade and there is availability then you'll be able to upgrade. Depending upon circumstances you may have to upgrade to an upgradeable fare class first

I figured as much - thanks