= [1003] Checkin fails with error message complaining about missing DTD
== Symptom
On checkin or import operations on DITA content, Cinnamon Desktop Client reports a missing DTD. 

== Background
DITA files, even though when based on an XML Schema, need an XML Doctype Declaration, otherwise DITA editors and DITA-OT don't function correctly. This declaration is misinterpreted by legacy Microsoft XML libraries in .net, trying to load the DTD which is not actually present (and not needed).

== Solution
The issue manifests itself in .net 4 and is fixed in newer .net releases. Upgrading to a newer .net release (like 4.7.2) fixes the problem.