If you’re doing them next year, then you’ll have AT and they will automatically get harder for you.
If you’re doing them right now and you’re not on AT beta, then you can jump ahead in levels for the same workout progression. IE if it is a level 6 threshold over-under workout, try doing a 7 or 8.
But as Jon said, harder != better. Having a little more aggressive recovery and progressive system might actually make you in a better super compensation phase and you end up being faster.