docx4j 11.2.9 is now in Maven Central.
This is a JPMS modularised release for Java 11 (or later) users. Java 11 users can use docx4j 8.2.9 if they wish; Java 8 users should use docx4j 8.2.9.
The driver for this release is to ensure the namespace corresponding to the w16sdtdh is declared when docx4j manipulates a docx containing that prefix (which will be the case for documents edited in Word following recent updates).http://schemas.microsoft.com/office/wor
... dtdatahash is new in [MS-DOCX] v15.0. Word (following recent updates) writes this namespace prefix to @mc:Ignorable in the MDP, for example, "w14 w15 w16se w16cid w16 w16cex w16sdtdh wp14". Since Word is unable to open a document if a prefix which appears in that attribute is not declared, the namespace must be declared.
Thanks to those who raised this issue.
To use docx4j 11.2.9 via Maven, just add one and only one of docx4j-JAXB-Internal, docx4j-JAXB-MOXy,
or docx4j-JAXB-ReferenceImpl to your pom. https://search.maven.org/search?q=g:org.docx4j
Otherwise, see https://www.docx4java.org/downloads.html