I like library providers that can provide mechanical upgrade instructions. For example:
model.adjust(x,1,y)
is now model.single(Adjustment.Foo, x).with_attribute(y)
Or whatever. Then people can go through your instructions find-and-replacing the changes, or even better, have an automated tool do it.
Also you pay some of the maintenance burden by writing all this documentation, so you have a some stake in keeping the changes minimal.
It's safest to sign. Safety is in numbers. Cowardice leads to the greater danger. And it doesn't matter if it accomplishes anything.