DPS keeps abreast of these changes; so all ePUB3 produced after the a Bulletin implementation date will contain the changes. However, since this may set up a conflict between the ACE tool and the file, recent changes may be withheld at publisher request. See below for an example of the application of standards.
For alt-text in covers, we follow Benetech guidelines, which recommend keeping short alt-text below 200 characters. When alt-text received exceeds this size it must be treated as a "long description" and incorporated in the appropriate elements.These guidelines are specified for covers: