To make sure everything was ok, we waited a bit.
The 1.10 update will now be made available to 1.09 cats, as an optional update.
This means your cats will have a "GET UPDATE" button in their menu, but will not show red text.
And for Yuukie's question: you can switch your cat anytime between low prim and normal prim count
Regards,
KittyCatS.