[EPUB Accessibility 1.1] refines examples and EPUB 2

[gregoriopellegrino]

In the document examples 6, 7 and 8 show metadata with the refines attribute. This attribute does not seem to be compatible with EPUB 2. What to do in this case?

Still many publications in EPUB 2 are available in the market (some even fairly affordable) and it is not certain that they will be upgraded to EPUB 3 soon.

For a11y:certifierCredential and a11y:certifierReport I don't see big problems (if there are not more than one in a file), but for the certication date (dcterms:date) having the metadata without refines be very ambiguous. Is there another way? May we add a note to use the example only in EPUB 3?

Do we put a note for all examples?

[mattgarrish]

There's nothing we can do to work around it. You can't structure the data, or chain it like in EPUB 3, so you have to live with ambiguities.

It's not a unique problem for the accessibility metadata, so I don't know that we need to call it out. I expect anyone trying to process EPUB 2 metadata is aware of the flaws. A human reading it, on the other hand, will figure out the association by proximity of the statements.

[mattgarrish]

Maybe we can note this in the "application to older versions" section rather than put notes everywhere that epub 2 metadata is not very expressive.