>> (53) The cache has been removed, but the acache-enable and
>> acache-cleaning-interval options have been deprecated? Does
>> this mean that they are still accepted in the configuration
>> file but no longer have an effect? If so, this should be stated.
>
> They generate a warning, but not a failure, when used. If that isn't clear
> enough, please suggest other wording.

How about:

The additional cache ("acache") was found not to significantly
improve performance and has been removed.  As a result, the
acache-enable and acache-cleaning-interval options no longer
have any effect.  For backwards compatibility, BIND will accept
their presence in the configuration file, but will log a warning
if it encounters them.

... and similar text for the additional-from-xxx options.