The cmake-policies(7) manual explains that the OLD behaviors...

on Fedora you see these warnings for at least a year now, pointed out on the mailing list long ago

do you wait until it fails after one of the next cmake updates?

The cmake-policies(7) manual explains that the OLD behaviors of all
policies are deprecated and that a policy should be set to OLD only under
specific short-term circumstances. Projects should be ported to the NEW
behavior and not rely on setting a policy to OLD.