%common.ent; ]> XML The XML DocBook DTDs. The DocBook Document Type expressed in XML. DocBook XML V&dbxcurrent; is the current XML version of DocBook. There is no official XML version prior to V4.0. DocBook XML V4.2 DocBook XML V4.1.2 DocBook XML V4.1.1 DocBook XML V4.1 DocBook XML V4.0