See a typo? Something has become inaccurate? While it is not something we encourage, it is possible to update published articles and issues at any time. You will just have to re-publish the Issue.
To do so just make your changes the same as when creating it. Then if you are ready to push changes out to subscribers, click Save, and then "Ready to Publish" from the Article. (If not, click Save Draft and it will take it offline so it will not be available for download.) Finally, click onto the Issue, and click "Republish," and that will push it out live with the changes.