Verified on 21x: https://qa21-mysql.nightly.sakaiproject.org/, build: a65af89d
20x: https://qa20-mysql.nightly.sakaiproject.org/, build: 115ff7f6 

Thanks,  We have incorporated this patch in our instances running Sakai 20 to avoid possible future failures. 

For this reasin we think  that it is important to merge it to 20 and 21 versions

Thanks  I just wanted to make sure I didn't miss something in testing. I will set this to verified because export/import is working.

, Last 6th or 7th April, url from http://www.imsproject.org/sites/files/question/qtiv1p2p1/XMLSchemav1p2p1/xmla/ims_qtiasiv1p2p1schema/dtds/qtiasifulldtd/ims_qtiasiv1p2p1.dtd was down and we (all Sakai around the world) couldn't export any assessment.

See: https://groups.google.com/a/apereo.org/g/sakai-dev/c/JH5dGrQNlSk

Core team decide put that dtd as internal. If export/import an assessment works then everything is ok. Thanks!

 Did you have a specific question you tried to export or some setting? I've been exporting and importing quizzes for the last couple of weeks, both .zip and .xml. For this Jira I had 3 multiple choice questions, exported and imported just fine. I checked 21x to see if I could reproduce the error, but it worked just fine.

That's what makes me wonder if it was something specific in a question that caused the problem. I would like to be able to reproduce the error on 21x or 20x before setting this to verified so I know I'm testing properly.