I have modified plugins/metadata/dc11/filter/Dc11SchemaArticleAdapter.inc.php using the Bugzilla solution: +9 lines -4 lines modification here:https://github.com/pkp/ojs/commit/067f5 ... cddc543396
[I also attach zipped my patched file]
My system now is ojs 2.4.1 with modified String.inc.php so that to disable mime.magic (not supported on GoDaddy shared server).
There are no other modifications, but possibly my 2.4.1 version lacks other bug fixes that were released by the PKP team in the meantime.
For now, I just inserted the e-ISSN number on the place of print-ISSN, and left the e-ISSN empty. At OCLC website, the ISSN appears only once, so actually I am satisfied as it is. My point is that currently, if you have empty print ISSN but filled e-ISSN, nothing is exported - just empty Source field. Can you confirm this behavior on your own test journal?