docx4j 8.3.4 is now in Maven Central. Being in the 8.x series, minimum supported Java version is 8.0.
This is a minor release, addressing some font related issues in docx to PDF via XSL FO output in v8.3.3 (released last week). Anybody contemplating v8.3.3 should use this v8.3.4 instead.
It also bumps FOP to v2.7.
To use docx4j 8.3.4 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