I asked this exact same question for the exact same reason and got no reply. My assumption is that it will renew at the new price and I will need to cancel prior to renewal. However I am expecting to get an email telling me about the happy news of my renewal before it happens (with the new price) so I can cancel then. If they don't send such a notice then there's a good argument for holding them to the old price given what they are showing when you look up your own details.

https://www.flyertalk.com/forum/35528145-post9.html